Could you use it with a 16 1/4" barrel in the meantime, or would that muddy the waters?
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Could you use it with a 16 1/4" barrel in the meantime, or would that muddy the waters?
No, that would be perfectly legal as far as I know, I just did not want to spend the dough for something I would not use more than once. The only problem I can foresee aside from the $ would be the tuning of the weapon. The process for tuning the gun involves firing single rounds and evaluating if the hammer and breech block springs need to be shortened or not. I would think the longer barrel would generate some greater blow back forces (could be wrong here) and I would have to have two sets of springs, one for the 16" barrel and one for the shorter one.
DOes that sound right?
Very well could be. I have fired the same carbine with both original length and long barrels, and it certainly seemed snappier with the long barrel.
That would certainly get me on the range much earlier than waiting for the ATF!
In a way, yes and no.Quote:
Originally Posted by 17thairborne
We're dealing with Newton's third law here. So it's mostly about mass (bolt weight). The longer the barrel, the more mass needed. The force pushing the bolt back hasn't increased. Only the time the bullet is in the barrel has gone up.
Without more mass the casing will be further back in the chamber when the bullet exits the barrel and the pressure drops. Not an issue for your Indy Ord bolt. It has plenty of mass. But with light bolts that relied heavily on advanced primer ignition as full-auto's, the casing can travel too far back in the chamber before pressure drops causing the case to bulge, split or rupture. The PPSh41 and PPS43 are good examples. With long barrels and lighter semi-auto bolts they will split a lot of cases and have very dirty breeches. But who reloads 7.62x25mm?
A stronger recoil spring will have a higher initial closing force, but there comes a point where the weapon becomes hard to charge. That can be overcome to a degree with a double spring system, like the Sterling has. The light spring makes charging easy, while the stronger spring captures most of the energy.
There's an section on blowback gun design in "The Machine Gun" by George M. Chinn. I think it's in volume 4. It also has all the formulas and it's a free download.
For my semi-auto Sten I made a small spring cup. (Same concept as the Sterling spring system). The cup keeps the light spring from reaching its solid length (fully compressed) and getting damaged when the bolt cycles. The cup has a hole in its center and slips over the spring guide rod with about 1 3/4" section of stronger spring behind it.
Thank you for documenting your build here. It's a lot of effort and much appreciated.
BTW, Building is very addictive.
Thast's a well thought out piece Vince. You know my views on API of course but that doesn't affect this situation of barrel length here. The Beretta 30's type SMGs have a long 9mm barrels and while it's not comparing like with like here, it's worth pointing out that we regularly used to fire them with standard government Mk2z ammo with no ill effect or signs of bulging.
What is interesting is that in our SMG barrels, they never exceeded the optimum 7" length. Which leads on to another question........... Who decreed that 7" was the optimum length? And optimum length for what? It COULD be the optimum length for mediocrity! Another interesting point was that during manufacture, breech blocks were constantly weighed and before being passed. had to weigh-in within a set of tight criteria. This was important when a different steel, of lighter or heavier density was being used and the weights were controlled by the depth of the central boreing in the rear end.
Oh for a lab where we could all gather after school for some extra after school physics lessons............. You mention Newton...... I used to take a Sten gun (dewat of course) into those lessons knowing that it was one thing that would really hold attention and make it a memorable lesson for its relevance. I used to wrack my brains for a similar small arms related lesson that could be used to realistically illustrate leverage, forces anf fulcrums......
Thanks, Peter.
I was wrong when I said, “the force pushing the bolt back hasn't increased.” If the muzzle velocity increases, and I think it does with a 16” barrel, that means the energy driving the bullet and the bolt increases too. Newton’s second law,,, F=m∙a or Force = mass x acceleration.
As for the optimum barrel length of a blowback open bolt 9mm SMG. It probably has more to do with the weight of the weapon than any of the other factors.
I am sure you have noticed how light Stens and Sterlings feel when they are stripped of all internal parts. The single heaviest part is the bolt (breech block).
If I remember correctly, there’s a significant increase in muzzle velocity between 7” and 10” barrels. Obviously this would necessitate a heavier bolt for the longer barrel.
There’s little increase in muzzle velocity with barrels longer than 10”, but they still require more and more bolt weight as they get longer. This is due to the bullet dwelling longer in the barrel. So, they are not what I would call “optimum” for a SMG.
At 7 ¾” the Mk4 Sterling barrel squeaks out a little more muzzle velocity and the bolt weight is still reasonable because of the double spring system and API.
Unfortunately we lose the API advantage when converting open bolt guns to closed bolt guns. So we need to add more bolt weight. The longer 16” barrel means even more bolt weight. Probably the best example of this is one you wrote about in The Guns of Dagenham, “Closing the Bolt.” The total recoiling mass of the Mk6 is considerably more than the Mk4. Not only is the bolt heavier, there’s also the heavy firing pin spring retainer included in the recoiling mass. It’s an ingenious conversion to meet US laws and all done before computers.
You reminded me of my boarding school math teacher. He had a training aid that held our attention for years. He was a large, barrel-chested retired Major General with a big bristling handlebar mustache and a booming deep voice. He had been a POW in Burma where the “Japs” as he disparagingly called them had removed his fingernails and two fingers from each hand. He would walk up and down the classroom with a riding crop tucked under his arm…when he wasn’t using it…on one of us. That was his teaching aid. Believe me, it worked!
Another aspect of bolt weight that I have not seen mentioned in this thread with respect to traditional submachine guns is the affect on cyclic rate. The lighter the bolt, the higher the cyclic rate.
In North America, it is simply not legally practical or possible to make a firearm identical to classic originals like the Sten. In Canada, there are privately owned original Stens, but ownership is limited to those who had them before a cut off date, and they cannot be taken to a range. '78 for autos, '95 for ones converted to semi. The IO, SAS and other similar operating systems allow a legal firearm to be made, using many genuine parts and retaining most of the appearance of the original. Shooting one of these reproduction Stens is not the same as shooting an original set on repetition. The sensation is different, because of the closed bolt function. The second pattern SAS uses a rather large cylindrical hammer; there is a bit of the sensation of movement that open bolt operation produces when the trigger is pressed, but the mass of the forward moving parts is much less.
Ah........ the light bolt theory Tiri...... This is one of those diminishing returns things where very soon the lighter weight does something - or rather DOESN'T do/allow something..... A bit like a lighter return spring thing. Let me read-up and come back on this. It is a well used discussion subject
When you've finished this project 17th, you ought to keep all this forum stuff in a file with your photos because you've certainly got some of the forum brain-power working overtime on your behalf here with some great thought provoking comments. Oh for that after school physics lesson. Just think of how we'd all be rattling through Newtons Laws and the laws of springs and compressions..... What is it now?
I never imagined this project would be so informative to me. Rather than a "wow...nice project", you guys are creating a classroom where free discussion rules the day.
These issues are truly providing me the beginning of an understanding of the dynamics of the many phases of the operation of the STEN. It reminds me of my early remembrances of firing, unlocking, extraction, ejection, cocking, loading etc. and having to memorize nomenclature;
"Sir, US Rifle 7.62 mm M-14 is light weight, air cooled, magazine fed, shoulder fired semi-automatic weapon"........
---------- Post added at 10:34 AM ---------- Previous post was at 10:27 AM ----------
Can't wait to fire it. Wish I had the experience of firing a STEN on FA to make a personal comparison. I had an FA M3 at one time and the feeling of the open bolt firing system was much different from say an AR on FA. Obviously completely different weapons, but the bolt moving forward before firing was always a bit "weird" to me. Such a slow cyclic rate of fir though that permitted occasional single shot if the trigger was managed well. I used to go shoot with a few friends on the ABQ SWAT and they loved firing the M3.Quote:
Originally Posted by tiriaq
An M3 cycles at about 6 rounds a second, a Sten about half again faster. PPSh maybe 2 1/2 times faster than an M3. Different desgn philosophies.
:) Glad you see it that way, 17th. I was feeling bad for rambling on in you build thread.Quote:
Originally Posted by 17thairborne
Yes, I know the feeling you're talking about. Both the M3 and the Sten are like that. The Sterling has a much better balanced feel.Quote:
but the bolt moving forward before firing was always a bit "weird" to me.
It looks like you're enjoying building your Sten. Give a Sterling some thought while the kits and semi-auto conversion parts are available. It's a little sweetheart. I am sure you would enjoy it.
With that rate of fire I suspect it would be very hard with the STEN to make is sound like an auto with repetitive trigger pulls in quick succession.Quote:
Originally Posted by tiriaq
---------- Post added at 08:46 AM ---------- Previous post was at 08:44 AM ----------
Wouldn't have it any other way. The more you guys add, the better it will be for us blokes building STENs. Any constructive comments, information or presumptions will all help. It's why I'm trying to be a little more detailed with the images and discussing the problems that I am having.Quote:
Originally Posted by Vincent
It's the slow cyclic rate (heavy bolt) that makes guns like the Sten suitable for conversion to closed-bolt semi-auto only. Guns with light bolts are not as suitable for these conversions.Quote:
Originally Posted by tiriaq
The Sten, Sterling and Uzi all work very well when converted, even with the long barrel.. 16" to comply with BATFE. But it's better to pay the $200 for the SBR tax stamp if you are converting something like the Papasha. It needs the short barrel. That's really the only way the laws of physics and the land will work together.
I have a F.M.A.E. PAF bolt. It's the Chilean copy of the Sterling. Some people here call it a "Speed bolt". The Mk4's ability to change bolts in a few seconds makes it excellent for demonstrating the higher cyclic rate of the lighter PAF bolt. You really notice the ROF change when you shoot one right after the other.
BTW, bolt weight is only one of the things that can affect the cyclic rate. There are others.
Getting close to the weld. I need to ensure I position the ejector properly before welding.
I'm going back to my problem with the slot for the ejector. You recall when the charging handle is moved up and forward it moves he block into the upper slot (safety), the bolt is moved forward and the rotation of the block puts a portion of the block over the grove where the ejector should be and the block will not move fully forward into its slot. I do not want contact between the two as that will damage the block or weaken the weld between the ejector and the tube. You CANNOT move the slot for the ejector, because if you do, the ejector will be in the wrong position when the block is moved forward to load a round.
You could mill the upper safety slot a little lower than depicted on the tube's template, but that leaves less metal between the upper charging handle groove and the lower. I think it would make it too weak. I think the proper solution would be to move the location of the safety groove aft (away from the ejector) by about 5/16" Of course Newton said for every action there is an equal and opposite reaction. Moving the charging handle safety slot aft will make it all the harder to pull the block to the rear and into the slot because you are compressing the springs tighter. That tiny handle takes a lot of rearward tension to compress two springs. I do think this is the approved solution though.
https://www.milsurps.com/images/impo...20error1-1.jpg
SInce my receiver tube is already milled, I have to work with the ejector. I filed the upper surface of the ejector thinner so that the block, when moved up and forward into the "safety" position would ride over the ejector with slight clearance. Here is the correction:
https://www.milsurps.com/images/impo...ctor1JPG-1.jpg
Here is how it looks with the ejector installed and the block in the forward (charged) position. You can see the filed portion will allow for the block to move forward when in the safety position. My problem now is that I've filed the ejector down to it's original height. That was done by removing the scrap from the original tube where it was welded into the tube. Now I've created another problem; ( the photo below shows the ejector installed too high. In this position it will not contact the backof the 9mm case. It needs to be moved down into the block groove)I should have left a bit of scrap on the top so that it could be wedged into the slot and moved up/down to create the proper depth of seating so that the tip of the ejector rides in the block grove almost to the point where it contacts the block. If you do not do this, the tip of the ejector will not contact the back of an extracted/fired case and cause the lateral momentum to sling it out of the ejection port with the spring aided extractor. In the photo below, the ejector must move down quite a bit so that it will actually do its job. When I move it down into position, I no longer have anything to hold it onto the tube.
I will purchase a stainless steel hemostat clamp, zip strip it to the front of the tube and clamp it to the ejector in the proper position so that I can tack weld it in the right place and use that to hold it into the proper position using the paper shims between the ejector and the grove in the block. If tacked properly, I can remove the hemostat and fully weld. When the hemostat arrives, I'll take a photo and post that.
If anyone has any other ideas please let me know. Its very tricky to get the ejector to sit properly between the shims and in the grove when you use a file like Jack the Ripper:madsmile:
https://www.milsurps.com/images/impo...ctor2JPG-1.jpg
Another option would be to just make another ejector, which would fit the slot in the casing, and interface correctly with the bolt.
17th,
Fighting the springs to get the charging handle into the “J” slot was too much effort for this old man. So I did the conversion on selector to make it safe or fire instead of R & A. It’s very simple. You just cut a semicircle out of the tripping lever for the selector to pass through. Let me know if you want the detailed instructions.
I used some of the wife’s pottery clay to hold the ejector and a strip of beer can to shim it.
~V~
Attachment 52107
You don't want the ejector to be flush with the outside of the tube. The weld will be stronger if it is sitting down in the slot. Remember the magazine well will be sliding over this. So the weld needs to be in the slot. If you get any above the slot, you will have to grind it off so it's flush with the tube.. or the magazine well will not go on.
Yea...that's why i ground off the old tube so it could sit down a bit lower and receive some molten metal on top, thus binding it to the tube. I would then file the excess off to match the outer contour of the tube. I suppose I should have left just a bit on to wedge it in there, yet provide room for the weld. I did not know about the mag interference issue...thanks for calling it out!Quote:
Originally Posted by Vincent
---------- Post added at 01:25 PM ---------- Previous post was at 01:23 PM ----------
I like both of those ideas. I'll get some pottery clay and thin metal for the shim. I was thinking of the selector conversion to a safety. IO adds instructions in their plans which accompany the "guts". If you would be so kind as to post photos of the mod that would be of great help to me and others.Quote:
Originally Posted by Vincent
---------- Post added at 01:30 PM ---------- Previous post was at 01:25 PM ----------
That brings up another question:Quote:
Originally Posted by tiriaq
By filing the ejector as I have, will there be strength issues with the part? It seems since I left the front profile alone and made my ramp down to the lower profile with a rounded bevel instead of a right angle, I should minimize the reduction in the strength of the part and not create a structual weakness. I mean....jeesh...we're only talking about knocking out an empty case that's held behing a spring extractor on one end. SHould not be much force impacting the ejector. Or am I a worry wart?:sos:
I will get a picture of the modified tripping lever and centering block up soon.
Don''t worry about you're ejector. You could file more away and it would is still be larger than the ones I have. They are shorter and still work fine.
Great....thanks
I don't really understand all the geometry that you are talking about except that there is a problem with the breech block fouling the ejector when the cocking handle is rotated uo and forwards into the safety slot. Is this correct? Bear in mind that I am not familiar with the single shot conversions too!
If this is the case, and it is a small amount of metal that fouls, then why not just leave the casing and ejector full size and unaltered - as it is - And simply machine away a small section from the front/side face of the breech block where it is fouling the ejector. The part that is fouling will be the radius of the outer forward edge and nothing to do with the important feed horns.
Or am I missing something in the telling here?
It sounds like the cocking handle slot is out of alignment with the mag port and ejection port by a few degrees. Does the sear align with the block OK (Or whatever it is with the semi conversion).
Peter,Quote:
Originally Posted by Peter Laidler
It is such a large amount I was afraid it would alter the block in a very negative manner. That is why I elected to modify the ejector. I would have to take off a significant portion of the block where the feed horns are. In retrospect, the proper solution is to mill the safety grove farther aft of where the template renders it. On another note, if I use the selector switch with the below mentioned modifications, it will serve the same purpose as the upper bolt handle grove. It will, in essence, eliminate the need to use the upper grove. I could have just done nothing and not used the upper grove at all.
MODERATOR
Please delete two previous posts with wrong and duplicate photos. Moderator edit: 2 previous posts deleted as requested..
Sear aligns properly. Block aligns perfectly with the ejector during the loading, 'locking" and extraction phase. Is only when the block is rotated up and into the safety slot that the feeding groves foul with the ejector. That tells me the safety groove is milled too "high from the cycling grove. The problem with milling it at the proper angle is that the grooves would be too close together there would not be much metal from the tube between the two grooves. Too weak in my opinion. THis is why I conclude that milling the vertical grove more aft on the tube would solve this problem. You an see the thin line where I edited the image to show where I would mill the new upper grove. That will move the block aft enough to where it will not interfere with the ejector. You can also see if i milled the grove lower (closer to the long lower grove), there would not be enough metal between the two. Too thin I think.
https://www.milsurps.com/images/impo...04/Tube5-1.jpg
Will the bolt still clear the bar in the center of the spring retainer if the safety slot is cut that far back?
Sure will. The length of the center bar puts it just behind the aft of the lower grove, so that's well in front of the upper safety grove.
It seems from reading and avidly following this thread that the drawing sheets that you have for your conversion aren't quite right for your Mk5. Sort of LOOKS like they are sort-of Mk2 modified for Mk5 if you see what I mean. I could be wrong of course but surely if they'd actually done what the drawings are made to illustrate/represent, they'd have discovered these minor (?) errors.
If I were you I'd set about correcting their drawings and your project and then ask them if they'll contribute to your project for your efforts on their behalf.
I did something similar with a newish petrol mower after I found that to get to something for a bit of winter lay-up maintenance (as suggested in the user handbook no less......) was a real pain in the ***! All it needed to correct it was two readily commercially available slightly longer bolts with captive washers and the two bolt holes elongated and opened at the end. They collected my used 1year old mower, investigated what I'd done, incorporated it into future production and gave me a brand new one and a small cheque!
I was forgetting you are using a new Breech block so could it be the Breech block machining that isn't the same as the original in the outside edge of the machining for the feed horns? How does it compare to the original block?
Looking at the photo of where the block interferes with the ejector, it looks to be about 1/2" long so would you not have to move the safety slot back the same amount for it to clear?
I like your idea. IO sells the tube as a MK V template. I have not found anything on any forum where a builder encountered the same issue with the ejector. I did mention to Jason at IO about the template's rendition of the ejection port. On IO template, it is depicted to match the length of the opening on the Magazine well, a bit too large, whereas on an original MK V, the cut for the discharge port on the tube is smaller. It is also cut narrow at the front than the rear, and on the IO template is is a rectangle. I made that change on my tube to mirror the original tube. I should have paid more attention to the safety grove of the original MK V, but its hard to know how the new block and operating rods will be impacted when trying to use original dimensions. Well...now I know.Quote:
Originally Posted by Peter Laidler
Blocks look the same. Sorry for the cr@ppy photo, but you get the point. The groves are machined the same so they will ride over the magazine lips. The bolt intrudes over the ejector slot by 5/16" at best. I think milling the safety slot 5/16" farther aft on the tube would solve this problem. I'll call Jason and see what he thinks.Quote:
Originally Posted by Brit plumber
https://www.milsurps.com/images/impo...mparison-1.jpg
Spoke with Jason about the issue and sent him the images.
Regarding the ejector/block interference:
Below is a link to a photo from another STEN builder's post: Notice how little material is left between the safety slot and the operating slot. That was my concern about milling the safety slot a bit closer to the operating slot as opposed to moving the slot aft 5/16"
I suppose in my case there's enough distance between the two that dropping it 1/16" will not make that much difference?
13 Photo by w9amr | Photobucket
Welding (TIG) tentatively scheduled for Friday. Will post pics and details as soon as I'm done.
Looking ahead to the finish. My research indicated that the STEN Mk V was finished with a dark grey phosphate finish and then painted with the semi-gloss black paint.
I am looking at Brownell's Manganese Phosphate kit. It is my intent to DIY the process and be able to do more with the remaining materials later.
Any advice for the novice? I read many of the MILSURPS posts regarding the process.
Advice........ might I suggest that you save yourself the bother and get BRian at BDL to do the phosphate and paint as he has the real McCoy process and I have seen his Mk5 Sten. Just my view of course!
If you do prefer to do the finish yourself, the process is quite straightforward.
I have not used Brownell's product - cross border shipping of chemicals is problematic - but a very similar product is available in Canada.
The carbine in the photo that I sent you was finished with Radocy brand Parkerizing process, apart from the magazine housing. It was painted. I had to sent the carbine to the RCMP for inspection, and wanted to get it in the mail, didn't have a batch of bits to park, and didn't want to get the system up and running for one piece.
The process is simplicity itself. I prepare the surfaces by blasting them with aluminum oxide grit at about 40 psi, and then immediately park them. Out of the cabinet, the parts are clean and dry. If there is any risk of residual oil or grease, soak the pieces in hot trisodium phosphate solution, rinse, and into the park. A stainless steel pot on a hot plate or bbq works fine. An enamelled roasting pan is also good. A cooking thermometer allows the temperature to be monitored. Just stew the parts until the colour is satisfactory. I do not like the idea of parking bores, and plug barrels using a threaded rod with seals, washers and nuts. Parking is much easier and safer to do than hot caustic bluing. Even then, doing it outside is not a bad idea, there are fumes. Once the desired colour has been achieved, rinse thoroughly in hot clean water. Dry and coat with oil to cure for a day. I have not applied a coating over a parked base. I do not know whether it is best to cure the park, and then remove all traces of oil, and apply the coating, or if the coating can be applied over fresh, clean park. I have only applied coated finishes to freshly blasted surfaces.
Instead of blasting, some folks use an acid etch to give a slight tooth to the surface.
The various spray coatings - some are catalysed to cure, others are baked - are easy to use, and are effective. Matte, semi-gloss and gloss blacks are available. Application may be done with an airbrush or some products come in aerosol cans. These coatings can be applied directly to clean blasted or etched surfaces, if desired.
Where? From whom? That's what's been holding me up here...Quote:
Originally Posted by tiriaq
Go to PJ's Gun and Metal Care Products. I have had excellent results with his park. solution and hot water bluing products. Found his cold blue to be inferior.
peter,
I do not doubt he will do a superb job. I am hoping to learn a few new tricks and skills through this project, and I have never parkerized before. I am also tying to keep the costs in mind to minimize total outlay by using my labor....and....yes...your expertise:beerchug:, which when the opportunity presents itself for a mutual meeting on either side of the pond, we will quaff a few ales of your choosing!
---------- Post added at 04:13 PM ---------- Previous post was at 04:10 PM ----------
Thanks it seems so, and Brownell has a very detailed description of the process to get the results correct. I am looking forward to trying.Quote:
Originally Posted by tiriaq
Peter is an Armourer so unless he has turned into a xxx since leaving the Army, he wont quaff his ale, he will 'Down' his pint to the chant 10, 9, 8.....3, 2, 1 on yer 'ead!Quote:
Originally Posted by 17thairborne
But then again he did take a commission so it may be a glass of port, and then some burning of the mess piano or other such antics that would get the rest of us mere mortals 14 days in the glass house!
For a minute there you had me doubting my understanding of the English language. To whit:Quote:
Originally Posted by Brit plumber
quaff kwäf verb: quaff; 3rd person present: quaffs; past tense: quaffed; past participle: quaffed; gerund or present participle: quaffing
1. drink (something, especially an alcoholic drink) heartily.
synonyms: drink, swallow, gulp (down), guzzle, slurp, down, empty;
Now I have never met Peter, but judging his profession, and having quaffed quite a few beers with British Officers in a lively bar while singing all manners of courageous tunes (out of tune), I was assuming I was characterizing his manner of drinking accurately. Or did I miss the boat here?:dunno:
The welding is complete. A friend of mine referred me to a local welder who did an absolutely fantastic job. The welds on the tabs that connect the trigger housing to the tube look remarkably like the original spot welds done by ROT in 44. They have a slight recess and were done with the utmost of patience. He used a TIG welder and extremely thin wire, I think it was 1/32". He began with a tack, and then filled patiently until the level of the metal was just below the surface of the tab. For the welds on the trunnion and rear attachment ring, those were filled to slightly above the level of the tube. Very little filing was required. Here's the goods:
"J" at work:
https://www.milsurps.com/images/impo...lded5JPG-1.jpg
Tabs welded to tube
https://www.milsurps.com/images/impo...lded7JPG-1.jpg
On display in the bunker
https://www.milsurps.com/images/impo...ded2bJPG-1.jpg
More detail, but need to finish cleaning up these welds
https://www.milsurps.com/images/impo...ded2aJPG-1.jpg
https://www.milsurps.com/images/impo...ded4aJPG-1.jpg
http://castraponere.com/bloodontheta...N/Welded4b.JPG
Coming along really well!
Thanks!Quote:
Originally Posted by tiriaq
Am I seeing picture distortion or do you have the cocking handle square to the trigger mechanism housing? All of ours had the cocking handle and cocking handle slot at an angle of, say roughly 20 degrees or so from the horizontal so that you could just cant the gun over to the left a tad and cock the gun with the left hand
Peter,Quote:
Originally Posted by Peter Laidler
You are correct. The cocking handle is set at 90 degrees to the trigger mechanism. I suspect that is the result of the design of the hammer in the block. It is placed at the 6 o'clock position and it's operating rod and spring are near the bottom of the block, also at the 6 o'clock position. The operating rod for the block, and its longer spring are at the 12 o'clock position on the block. I suspect any attempt to drill a recess for the charging handle in the block in other than the 3 o'clock position would cause interference with the cavity of the block's operating rod.
In order to provide a proper position for the hammer, it must be placed in the 6 position so that it can interact with the trigger/sear/interrupter system. That leaves only the 12 position for the op rod, as placement any where else than 180 out from the hammer would create lateral forces within the tube. 180 out between the two rods and springs places the resultant force in the center of the block along the longitudinal axis allowing the block to move fore and aft without torquing left or right as it moves. These lateral forces would inhibit proper functioning of the block in its forward/ rear movement. Please check the physics on that.
It would be more accurate to design the slot for the charging handle as you noted, but I do not see how it would be possible. This highlights the one deficiency of this design: the dual stiff springs and the location of the charging handle make it extremely difficult to cock with the left hand. That makes this an ineffective combat weapon (in it's IO semi auto config). It does, however, remain in my opinion, a near faithful representation of the original STEN Mk V while keeping the ATF laws in mind.
In addition, ATF doesn't like the cocking handle slot in the original position. Just another redesign feature to keep an original bolt from being inserted. This is the same reason why the ID of the main casing is smaller.
There are semi auto Sten designs in the US which use reworked original bolts, modified for closed bolt operation. Sometimes diameter is reduced, sometimes a "denial bar" is welded into the main casing, with a corresponding groove machined into the bolt, to keep an unaltered original from being easily substituted.
ATF will not accept an open bolt design. Viewed as simply too easy to convert to auto.
I do not recall ever seeing a Mk. V parts kit for sale in Canada. Lots of Mk. II parts, though. Mk. V was never really a standard Cdn issue; have seen only one photo taken in Canada in which the front end of a V barrel can be seen. The Mk. II parts are from Stens demilled when the Sten became obsolete here. I know of one chap who reworked II parts to create a V type.
Thanks fort that useful info 17th and Tiriaq. I know a person here who partially stripped a deac/dewat Mk2 to make an equally deac/dewat Mk5 and I have to confess, made a superb job of it.
But didn't it bring on the pains.................? His local Police took it upon themselves to intrerpret this as trying to reconfigure it back to something shootable. Anyway, a simple school lesson type very simple explanation over a cup of tea, explaining that NOTHING of the dewat/deact work had been tampered with or otherwise messed with, followed by an hour on the range with the real McCoy convinced them. Naturally, a week later, their boss and the head of the firearms licensing office had to be convinced as well followed by a jolly on the range with a Sten, Uzi (or was it a MAC?) and a Sterling..................
Looks like you are getting close to test firing.
Vincent,
Yes...getting close from a construction stand point, but a long way off waiting for the ATF forms.
On another note...found this cool British pamphlet detailing the operation of the MK I and II.
https://www.milsurps.com/images/impo..._0366JPG-1.jpg
---------- Post added at 04:29 PM ---------- Previous post was at 04:27 PM ----------
I sometimes wonder when they'll come a knockin' at my place. It's a struggle between posting what is fully legal and worrying about mis-interpretation.Quote:
Originally Posted by Peter Laidler
While ATF does sometimes amend their interpretations, I doubt that you have anything to worry about. You are doing it by the book, and jumping through all the hoops.
The carbine you are making meets all current specifications, and you have been above board, applying for the SBR stamp of approval.
No idea about NM state law, but I expect that you have insured that you are in compliance.
Did you use the online application? I hear you get your tax stamp back much faster than with the paper form. I just used it for the first time.Quote:
Originally Posted by 17thairborne
It was down for long term maintenance when I tried. How well did it work? Was the fingerprinting system easy to use?
Let’s say it’s a good start. Something they can build on and improve over time. It’s not all intuitive. Scrolling is a bit of a pain. But it’s an online process and that’s a huge improvement. Gave my credit card info and got an email back, just like buying anything online. It was so easy, now I am tempted to buy more stamps and build more NAF stuff.
I have a NAF trust. Didn’t see a fingerprinting system.
On another topic… how do you post your pictures on the site? I always get the thumbnails.
https://www.milsurps.com/images/impo...ded2bJPG-1.jpg
And what’s this guy holding? Is it a “brick” explosive charge? The kind used in WWII?
I think the trust is the way to go, and I need to set one up. Was that cumbersome? Forgot the Trust does away with fingerprints, because you can't take a Trust's prints:p Is the NAF trust different from any other?
As far a hosting images, my wife signed us up for a Filezilla account for our various projects. You simply drag your images to the folder in your account and they will show up on your index page. Simply link the image in the thread to your file location which is unique for each image and it's there.
To post, you simply copy the link for the image at your filezilla folder, paste it between the following characters:
[img] paste here [/img]
Since I collect items from or attributed to the 139th Airborne Engineer Battalion, including inert demo items, I also collect some German WW2 inert engineer things as well. The engineer is holding a German inert 1kg demo charge with inert fuse. Supposed to be a training display, I just hung the STEN there for a photo.
Here's a more inclusive view showing engineer circa Mar 45 on the left, another undergoing parachute training 1944, and an engineer conducting training with captured German demo items at Chalons, France circa Feb 45:
https://www.milsurps.com/images/impo...05/3guys-1.jpg
I drew up the NAF trust and paid a local attorney to check it. It’s basically a revocable living trust. There’s not much to it. This was many years ago and NAF trusts were not as common as they are now. Today you can get one done for around $100.
I live a half mile from the county line. Our Sheriff (CLEO) would sign the form, but the Sheriff in the next county wouldn’t. Those folks had to get a trust if they wanted any NAF items. That told me I should get a trust. Because you never know when the good folks of your county might elect a democrat as Sheriff… and then you’re ....’d and you will have to get one anyway. So, yes… a trust is the way to go.
That’s a very nice display you have there. Many years of collecting I’ll bet. And thanks for the info on the demo charge. It has been 55 years since I have seen one. My father called them bricks. Four or five together was extremely impressive to a young lad.
Off track a bit but I am about to have 30 Mk5 Sten gun butts machined up. A simple job in itself. Has anyone out there in forumland got one with a flat steel butt plate? Can anyone send me detailed dimensions. Easy to have water jet cut and together, make the butts simpler to machine than the brass butt plate version
Quote:
Originally Posted by Peter Laidler
Peter....wish I had one, as you see mine is brass. I mean the butt plate :lol:
Update from ATF...Jan 15 for the approval. I was planning on doing all the sand blasting and finishing together with the barrel when I buy it so the finish matches. FO now the project is pending....like my ATF FOrm 1!
Terrible news on the MK V rebuilt front! Apparently Century arms, who did the STEN Mk V dewat work, did not properly cut the receivers to fully comply with the ATF rules regarding a gun parts kit. The kits they cut and sold to APEX arms were still considered live MGs by the ATF so they are recalling them. They state they will pay for shipping, cut the receivers IAW ATF standards and return the kits. Since my tube is already cut off of the trigger housing, I will be fine with sending the tube that I so wretchedly cut to shreds (thankfully), otherwise I would have had to send the whole kit back. I confirmed this with the ATF technology branch today.
Century Arms is having to recall over 500 kits. I was wondering what happened to the stock of them as they suddenly disappeared from every website about 2 weeks ago. I was hoping to make a Mk V (S) with paperwork later. Will have to wait until this issue is resolved.
https://www.milsurps.com/images/impo..._TubeJPG-1.jpg
Phew........ How DO the BATF want the main body cut?
I have to say that I admire your tenacity with this project - much the same goes for Vincent with his pheonix patchett rebuild too.
Back to the first 'cut body' photos again, I liked the wood patch on the pistol grip. That's how we used to repair the sides when the thinner top-rear end collapsed or broke away. Later there was an instruction that when it did break away, we could just make-good. There weren't many Mk2 and 5 Stens still sloshing around by the late 60's but there were always plenty of mechanical parts - but not the woodwork so we had to patch. What a chore, knowing that within a couple of years they'd all be gone except the silenced Mk6's. But like they always say. Looking back, it didn't do us any harm and was 'character building'
Are the ATF that stupid to think that once a STEN tube has been cut it would be easier to repair it rather than just make a new tube? And what happens if they can't recall all the kits? If someone bought one and resold it a few weeks later to someone who sold it on at a show etc. what then? AFAIK, when they are demilled they are non guns and can be traded freely with no records to be retained. When will the idiots who make these decisions wake up and smell the cordite?
Very crazy situation and you make a good point. It would be very easy to purchase a tube that matches the original diameter and mill the slots to spec instead of trying to weld and refinish a piece of tube onto the cut portion. I suppose they are sending a signal to all the companies that if they do not comply explicitly with the specifications for deactivating, this is the outcome. Think of the pain in the *** for the 500 who purchased these.
Regarding the resale, the company is asking for names and addresses of the purchaser if the item was resold. I think of the confusion for those who sold these gun kits (not technically a firearm) to someone else thinking they were selling gun parts and now they in fact sold an NFA firearm, ignorant of the fact that all of this had transpired. According to the courts, "ignorance of the law" is no defense. What a shi#y can of worms this could be.
Low and behold...
Century Arms STEN Mk5 kit recall....WTF!!
Surprise...surprise, my ATF Form 1 came in today. It took just at 7 months from the day I mailed it. I will begin by ordering the barrel and researching the phosphate finishing process.
Good to hear you got it.
Show us some pictures when you're finished.
Thanks...will do!
Look forwards to your progress. Brian at BDL can do and paint to the UK MoD spec
Peter,
Thanks much for the lead on the front sight.
Just ordered the IO barrel. Will post images when it arrives.
oz
Front sight parts on order from BDL.
Glad to hear that there has been progress!
Thanks...still waiting on my barrel!
Here are the images of the new barrel installed. It's raining something fierce in NM today. Supposed to get 9" in the next 24hrd (rare). Will take it out and give it a test firing. The springs have been worked and shortened IAW the instructions. The barrel fits nice and snug. test fitted a round in the unattached barrel. Will post video of the test firing when done.
Once my front sight assembly comes in from BDL, I can fit that then I'll tackle the finishing.
Have you test fitted the bayonet? It looks good so far...
I don't have a bayonet yet! Am working on accessories. Will test fire without the front sight to get the spring tension/length correct.
Spike or blade bayonet?
Spike bayonet, unless you find a no 7 bayonet.
Probably easier to find a spike.
Front sight parts sent yesterday Oz by Priority Mail. I have plenty of nice British spikes if in need. The No.7Mk.1 blade bayonet is also correct but I don't have any at the moment.
---------- Post added at 01:37 PM ---------- Previous post was at 01:37 PM ----------
Still got lots of newish condition mags too if in need.
Gents,
Thanks for the recommendations on the bayonet.
Brian,
Thanks for the update on the sights. I'm good on the mags, have 5 of them various makers, and will probably catch a spike from you. Will keep looking for the A/B bayonet web holder with the small side pouch!!
oz
Quote:
Originally Posted by Brian Dick
Sight arrived today. Top notch MINT condition. Dry fit just fine. Thanks Brian!
Raining cats and dogs...will test fire soon!
oz
Brian's sight dry fitted!
Always nice to add the paperwork! Added this Canadian reprint of the 1944 Machine Carbine pamphlet which features the STEN and the Thompson
Some days are not good!
1st Trip: combined 8 errands into town then out to the desert to test fir. Sh!t...I forgot to bring the STEN.
2nd Trip" 2 hours later...ready to go...Dang thing won't fire WTF? Ooooh....no firing pin!
Will try again on a better day when the rest of my useable brain is with me
:-(
I wish I could say I haven't something similar.
The man firing the Sten and Thompson in those books was WO2 Paddy Eustace from the Small Arms School when it was at Bisley
Thanks for sharing that history!
Yep....., that's him. He is the one featured in the Sten gun pamphlet too!
Finally, the weather and my brain are clear enough for the first test firing. Armed with the STEN (and firing pin), safety materials, cleaning rod to check the barrel, ammo, camera etc I took to the desert to check my efforts. The ammo was Winchester 9mm, 115 grain, fmj. I fired at a range of 15 meters.
1. Test fired one round from an original magazine. Feeding was uneventful. I held the weapon in such a manner as to prevent any rearward flying components from striking me. The weapon fired without a problem and the spent casing was ejected slightly forward of the 3 o'clock position and about 5 meters from the weapon.
2. I loaded 3 rounds into the magazine and fired each one slowly, again with no feeding problems.
3. Next I tried a 15 round magazine firing at an average rapidity. Again, no problems whatsoever.
4. I fired a series of 25 round magazines at differing rates of semi-auto firing, again with no issues.
5. The final test was with a 25 round magazine at rapid semi-auto firing. Flawless.
OBSERVATIONS:
a. I am extremely pleased that the weapon functioned without one fail or malfunction through 150 rounds of ammo.
b. I had adjusted and seasoned the two springs in accordance with the IO instructions. I did not have to make ANY adjustments.
c. I constructed and modified the selector switch iaw IO instructions so that it functions as a safety. In the A position, the trigger can be pulled, but the tripping lever does not release the block. In the R position, it fires in the semi-auto mode. This weapon will not fire in FA.
d. I would not use the A position as a safety. Placing the bolt handle in the upper slot leaves the block aft and breech open. That is the preferred method for me.
e. I am amazed that there is virtually no muzzle climb during rapid firing. The barrel can be held on target easily while firing from the hip. VERY controllable.
f. Virtually no recoil is felt owing to the nearly 10lbs weight of the weapon and magazine.
g. The casings seem to have a few more dings to the base than I am used to seeing. I've added an image for review.
h. The barrel seems to be well grooved as the spent round is nicely marked.
i. Post firing inspection of the gun revealed no damage or adverse wear.
j. Most of the spent casings were within a few inches of one another indicating a very constant ejection.
k. Final Observation. I used my video editing software to time the durations from the first round firing to the last. It took 4.009 seconds to discharge 25 rounds. That equates to a 366 rpm rate of fire in SA. Not bad.
https://www.milsurps.com/images/impo...4/09/9mm-1.jpg
Here's the video link:
STEN Mk V on Semi Auto 25rnd Test Firing - YouTube
Excellent, excellent, excellent! Finally to the far end of where we started. Top rate test and thanks for the vid on same.
Let us know if I got lucky sending the +.060 front sight blade. I only had my own Mk.5 to reference. When you target it it'll be interesting to see. Function looks great! Good job.
THanks for the morale support guys!
You bet Brian, when I get it refinished I will install the sight for accuracy and work on zeroing it at 25 meters. For now the blade is simply set within as a general aiming device. I did try a few shots at about 75 m and it was consistently to the left, (but not by much) as I had not pressed the blade all the way to the center. Will do that at the "range"
oz
Just a minor point, but holding/firing a Sten by the magazine is something for the cowboy films Oz. The left hand is wrapped around the barrel jacket. But great to hear a Sten gun again. Like they say...... You can use a £50 walnut stocked and blued Thompson gun that has been shipped across the Atlantic - or you can use a £2-7/- Sten gun. But you can only kill a man so dead!
I sure did love my Thompson though...
Superb job!! Looks like all the effort you put into this has paid off and you now have a very nice Sten. That’s some nice trigger manipulation too! :thup: :thup:
Hard to say what’s causing the additional dings to the casing base. Any witness marks on the bolt?
When I built my IO Mk3 Sten I tried using the original extractor. The hole in the bolt for the extractor pin was in a different location, so the extractor wasn’t in the same geometry as on the original bolt. The casings were getting beaten up. I removed the extractor and test fired a few rounds. They looked good and I made a new extractor with the correct geometry. Case hardened it with Cherry Red.
Where did you get the barrel?
BTW, To add a little to Peter’s comment about holding the magazine. I was taught to put my left hand around the barrel jacket because it gives better control of the weapon and speeds up getting an accurate aim. That seems to be true for me. I hold the Sterling with my left hand as far forward as possible… knuckle of index finger up against the guard and thumb near the barrel support. Give it a try and see what you think.
There’s also the danger of an out of battery detonation. They are fairly rare. I have only experienced two. Both probably caused from dirty ammunition.
They happen when a round doesn’t feed into the chamber. The heavy blowback bolt has enough energy to occasionally ignite the primer. As the cartridge case is not supported by the barrel chamber it erupts and shards of the casing can be discharged with the powder blast around the magazine and through the ejection port. It’s an unpleasant experience if your hand is there. I was taught better, but my hand found its way there once as I anticipated the need for a magazine change.
**
I like my Thompson… but I love my Mk4 Sterling. My wife even calls it “the other woman.”
Gents thanks for the safety comments. I will heed them. Here was my concern since my muscle memory of gripping a STEN consistently does not exist, I did not want to chance sticking the pinky in the ejection port. THis is what I was concerned about:
https://www.milsurps.com/images/impo...IMG_0637-1.jpg
Instead I elected to grab the mag well, not the magazine itself as I did not want to impart any torque on the mag and cause a misfeed. (video looks like I'm gripping the mag). Although this prevents lost pinky, it would not prevent burned hand as mentioned earlier. It did seem much more comfortable when firing in this manner.
https://www.milsurps.com/images/impo...IMG_0638-1.jpg
Peter your going to have to give these boys in Arnhem some grief for their improper weapons handling!:madsmile:
https://www.milsurps.com/images/impo...th20sten-1.jpg
---------- Post added at 12:36 PM ---------- Previous post was at 12:35 PM ----------
Barrel is from Indianapolis Ordnance as are the guts, tube and misc parts. I will take a close look at the bolt and extractor and see what it looks like.Quote:
Originally Posted by Vincent
Peter,
Since we are on the topic of gripping the Sten Mk V, I was wondering if you know of a source for either original or repro fore grips? I realize they were deleted in 45 because of the tendency to cause the barrel nut to screw loose and for the problems with the screw splitting the handles.
I have the Mk 2 barrel shroud with the two rows of holes, so the band would fit over it nicely as originally intended. Granted...I would have the two problems that you document in your book, but it would look correct for 4 and perhaps even into early 45.
ANy comments greatly appreciated!
I put one of these on
Attachment 56586
That's a smart idea!Quote:
Originally Posted by gsimmons
I got it from Michel Perrier Militaria in Canada. militaria.qc.ca. As Peter says you'll only do it once!
Ah, yes....... It has emerged that that photo was posed for AFTER the event at the power station some way from the battle, during subsequent filming. You can be rest assured that you will NOT lose a finger if it gets caught in the ejection opening and hit with the breech block. I know that from first hand experience on a Mk2. And a Mk5 is less liable to do the damage that a Mk2 did!
Foregrips...... There are a couple advertised on that auction site but are not even remotely like the real McCoy. The real McCoy is simple to make
IMA in NJ had the fore grips. I'm not sure if they still offer them or not. I have one installed on a spare barrels. It's not too bad once I blasted, Parked and painted the metal.
Did you know the Sten Mk.5 was the first military firearm in British service to come from the factory "as new" with the phosphate and baked Suncorite 259 finish? It became the gold standard of rustproofing on British weapons and accessories from then until just a few years ago when it was finally deemed obsolete in MoD service.