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Hi,
My M1 Carbine has a striking problem, but only when the barrel is pointed down...
(Case length is 1.280" and the bolt safety check is ok).
I found some ideas by consulting the carbine forum archives , but nothing conclusive for the moment.
Any help would be appreciated.
Regards
1.280 is the minimum case length. This by default increases head space. I would find some ammo with case lengths closer to 1.287 or so, which is what most commercial ammo measures. In other words….longer cases move the primer closer to the firing pin. If the action is a little lose, short brass aggravates the problem. Minimum trim length is 1.280, but that assumes the action meets head space specs.Quote:
Originally Posted by donki1967
I also lean for a headspace problem, especially since this rifle is a mix master based on RMC, Winchester and IBM parts, but this M1 is very accurate despite everything.
The problem is my available brass is short in length, S&B trimmed to 1.280".
There is a fairly easy way to check head space using a case of known length, strips of scotch tape and an accurate measuring tool. If it is much longer than 1.300, it very well might not fire case lengths as short as 1.280. I have known some people to install a longer firing pin and keep shooting.Quote:
Originally Posted by donki1967
I’d still be looking for some ammo with longer brass, I just don’t like shooting stuff that short. Of course, you may have some other issue, but you have to ascertain the condition of the action to start ruling-out possible problems. Usually, the extractor will hold the case close enough to the bolt face to fire, but the only explanation for the failure to fire when the muzzle is pointed down, seems to be the case falling deeper into the chamber away from the bolt-face.
Have you checked firing pin protrusion?
The firing pin protrusion seems to be true, but on the 3 fired cases I can see a primer push back, measured at 0.014 from the case base.
If you're just firing live primed cases, that will happen. There's no chamber pressure to flatten them out. Try a factory new case and prime them to test. You must have a couple factory new cartridges around?Quote:
Originally Posted by donki1967
Agreed. If primers back-out on fired live rounds, that might be another indication of long head space.Quote:
Originally Posted by browningautorifle
Jim
The rounds that I fired were live, loaded with 12.2 grains of VITHAVUORI N110 powder.
Nothing wrong with this load, very good cycling.
Some pics from the fired case
I think we need to get back to evaluating head space. Backed out primers on fired rounds really can signal long head space as well as the light-strikes on short brass.
I agree your load is probably ok. 12.1 is the published start for N110.
I will be happy to pm you about how to make that measurement.
I made an artisanal test to increase the length of the cases by using stickers for shooting targets.
Barrel pointed down, stickers on the primed case bottom:
1.280 Nothing
1.281 Nothing
1.282 Nothing
1.283 Bang
Gentlemen,
for today I give up ...thank you for your help.
I would give the FP a very close look. I bought a few spares that looked great, but under a good lens, they looked like a volcano, big chunks of hard face off, pits, dents etc. The extractor also grabs and should hold the case hard against the bolt face, making excess headspace a non factor. Buy some new cases from say Remington and the length will be all over the map. Some short, some long, some very short. I would try swapping out the extractor and making sure it is fitted correctly against the bold recess (many are not, many have never been apart). A new extractor spring might help. Point being: A great many carbines are long on headspace but still work fine. Consider that many,many bolts have never been taken apart and cleaned (the hole and spring) making the extractor a critical part in your puzzle.
Many of us fall into the category of thinking long head space is greatly overplayed. It’s something collectors get gitty over, but that’s okay too. The carbine chamber fully supports the brass and ruptures are much less likely. Can’t say there never has been one, but they only rupture I have read about was eventually traced to poor quality ammo. SAAMI gives you 22 thousandths when considering a 1.280 case and a 1.302 field gauge. Carbines will continue to shoot well past 1.302 with the right length brass. Like mentioned, if the extractor won’t catch the rim, or the head space gets seriously long…it might not shoot.Quote:
Originally Posted by DaveHH
If the headspace measures from the case front edge and the case is short (as most are) there is nothing to keep the base of the case near the bolt but the extractor. Without the extractor, the round would just lay in there at whatever length the case is cut. Long cases are dangerous, so short cases should be safe. The extractor must be sharp, correctly shaped and have no chips or faults. Beyond that, the extractor must have enough movement to snap over the rimless case and stay there when it does. You should be able to put your thumb on the extractor and make it move back and forth watching how much movement takes place and how much effort is required to move it. I've seen the extractor pawl hole so full of crap and debris that there is zero movement. Same with the ejector spring hole. Having the extractor pound against an immovable object without moving itself has got to damage something and it usually is the extractor or pawl. That is why it is essential to take the bolt apart and carefully examine the bolt, the shelf that the pawl plunger rests on, the springs and clean out the holes. I had to take a jeweler's file and refresh the pawl and shelf on my original Winchester as I didn't want to have to change any parts. The pawl was installed backward and had been that way for decades.
I agree with that the extractor is a bit hard to move, but I don't have the tool for disassembling the bolt.
I will soak the hole in kerosene and work the ejector and extractor with a case.
(The extractor moves better on my Garand bolt...)
Bolt head pics will follow soon.
Have a nice day.
Attachment 118202Attachment 118203Attachment 118204Attachment 118205Gentlemen, while inspecting the recoil spring guide I noticed that it was slightly crooked, do you think this may be a cause of my problem?
BTW, the operating slide spring has the good length, and seems not to be damaged.
Not likely as long as the operating spring force is sufficient to strip a fresh round, close, rotate and lock the bolt. I just assume here that you have observed the bolt lock up. If the slide is not able to fully lock the bolt, then it might be far enough out of position that the firing pin tang is blocked by the bridge safety, which would cause it not to fire.Quote:
Originally Posted by donki1967
I'm not sure now, but I thought I observed that at the end of the striking motion, the bolt lug locked a little more to the right.
If the slide cam does not fully rotate the bolt due to binding weak spring, bent guide or rub, when the hammer falls against the rear of the bolt, it will rotate the right lug on down….you can see that movement. You have to notice closely and use a case in the chamber. On an empty chamber, the bolt will usually move a little….make the observation with a case chambered. A dummy or live round (in a safe place) should be in the magazine to be stripped. Some force is lost on slide closure and you need to make this observation by stripping a round to get a factual test.Quote:
Originally Posted by donki1967
If a carbine bolt has not fully rotated, it might still fire if it has rotated just enough to release the tang on the firing pin. Exactly when this occurs is carbine specific due to wear and tolerances. Or, it might not fire, or fire sporadically. Firing out of position can easily crack the right bolt lug…or worse.
If in fact that bent guide was binding the spring, it certainly could have led to improper bolt rotation. Rotated just enough to fire randomly.
This, of course, is just a guess. I don’t have the carbine to see what’s happening.
During dry firing they will do that. Live firing, I can't imagine how you'd be able to see that.Quote:
Originally Posted by donki1967
I agree with that. Just trying to grab straws with OP.Quote:
Originally Posted by browningautorifle
I wouldn't get on the excitement plan. This is not unusual stuff not particularly hard to fix and your carbine is going to be fine. When you get your bolt tool, be careful when using it, the pawl can be broken if you get too frisky. Many of these guns have not had the bolt taken down and cleaned since Korea or even WW2. People on these forums do things like boil them to clean them as opposed to taking them apart. I would advise buying a couple of new extractors and plungers, you should have spares anyway. A new recoil spring (Not Wolf springs). These things are an absolute riot to shoot, so handy and light yet so deadly.
Good morning
Here are the bolt pics, regards
Some pictures show a rather flat nose on the firing pin to me. Can you post some pictures of fired brass showing the pin-strike?Quote:
Originally Posted by donki1967
Regards
The fired ones show us they went off. The ones that misfire would tell us more.
Is it possible to have too much FP protrusion? My fired cases appear to not be as deep a hit and are slightly flattened.
I would say that if one is perforating primers it might be a cause for concern. I have one carbine that did perforate Federal primers, but Federal’s are generally known to be one of the softest. I was tempted to shorten a pin a bit, but opted to stay away from Federal’s. I think as long as it’s not perforating, it would be okay.Quote:
Originally Posted by DaveHH
There is a range of protrusion. Don’t force my old memory to be correct on this, but it’s close. I think like from .045 to .080.
The one I have perforating Federal’s measures .074.
Bingo?
I looked up FP protruson in my big Army manual. Min: .048 Max: .065
It also said to remove and replace all plunger springs and plungers.
Consider that the FP was one of the most troublesome parts to manufacture, usually because of poor heat treatment. There are probably a lot of oversized FPs floating around. A lot of spares that we buy have been used before. Why were they removed?
Well…I only missed my guess by half-a-mile on the long end😁. I have been tempted to shorten my pin a bit, but I did that once to a pin some years ago and polished too much off. Wound up throwing it away.Quote:
Originally Posted by DaveHH
I will mention another possibility. There can be a slight difference in the machining of the bolt channel depth that will cause a variation in pin-protrusion. There could also be a slight variation in how the shoulder on the pin is machined as well. Everything is built to a tolerance and maybe every pin and every bolt can vary enough to alter pin-protrusion with a particular combination. I have pursued my perforating issue by comparing the same firing pin in a few different bolts and protrusion can vary among bolts.
I just do not want to shorten a pin rendering it bolt specific, so I just went to a harder primer.
" a striking problem, but only when the barrel is pointed down"
https://www.milsurps.com/attachment....2&d=1624597310
In this picture below, the rounded tip of the firing pin looks broken off. Like Floyd pointed out it looks like a Flat nose. I wouldn't be surprised to see the slotted area of the Firing pin is wobbled out where it intersects with the stem of the Extractor... Allowing the Firing pin longer travel. Have seen this before.
If you enlarge the OP's last picture of the bolt face... You can also see under the Plunger cone that the extra webbing (below the left side of the Extractor) has a rough/burred area. To me the Primers have a larger diameter impact area, not like a U imprint the spent casings in my hand look like. Maybe this 'Blunt Impact' is in part the reason the Primers are backed out?
If mine, I would swap out the Firing Pin, File away the rough edge on the bolt Web, install a new Extractor, Plunger Spring assembly, and install a new Ejector spring. If the Ejector tip is in good shape and working properly it could stay. But for a few $$ more you could have a rebuilt bolt and change the Ejector tip/spring assembly. Anything still in serviceable condition become extra parts.
I'd be interested in seeing a Macro pic of the current Firing Pin tip.
https://www.milsurps.com/attachment....7&d=1624522462
Pic from a Auction showing Firing Pin Tips:
https://www.milsurps.com/images/impo...55939672-1.jpg
To me, it almost looked like pictures of two bolts. A couple shows a possible flat tip, but one for sure looked normal to me. The strikes on the cases OP posted looked just fine to me (the strikes I mean), but as already mentioned, they are the ones that fired.Quote:
Originally Posted by painter777
Charlie, click on those in post #23. They go so "macro" you might have trouble finding the firing pin. :D - BobQuote:
Originally Posted by painter777
Attachment 118225
Hi GIBob,
I used his last bolt picture from reply #23. To me the Tip looks Flat, not having the rounded point we'd expect. And the Primers look Punched instead of Poked.
Could just be me, but I believe the Firing Pin is the problem or part of it.
I'd rebuild the bolt and file that Webbed edge smooth.
Floyd and Double HH are good at finding the Squeaky Wheel and fixing it. Can't get our hands on all of them. Guess we just wait and see what the OP can figure out.
After just reading the first couple lines, With it acting up with muzzle pointed down had me thinking at first that maybe his Trigger wasn't resetting until I read farther.
Haven't been on in a while, Doc has me at a Activity level of 2 on a 1-10 scale until some test results come in. Naturally it couldn't be worse timing with me trying to finish up the rifle club carbines, some big Maple and Oak trees being removed and me just starting wrapping the eaves and fascia in Aluminum. Damn I'd hate to be busy! More rain next few days so I'll try to catch up on Emails and PM's.... until the Meds say Nap time :(
I think we need to revisit this test. In think we still need to ascertain the actual head space. Maybe firing by lengthening the case with these stickers caused it to fire, but unless the primer has been moved closer to the bolt face, I can’t see how this helped. Like already mentioned, firing empty primed cases will usually result in backed-out primers. Long head space can also result in backed-out primers. I don’t think we really know at this point if OP has shown us fired primed empty cases or live rounds.Quote:
Originally Posted by donki1967
I just think an accurate head space measurement is in order and the bolt has to be striped for that. Everything else on/in the bolt can be examined as well.
[QUOTE=flydthecat;501374]To me, it almost looked like pictures of two bolts. A couple shows a possible flat tip, but one for sure looked normal to me.
It's the same bolt, I would like to have a second one for testing in my carbine
If I understand it, the Boxer primer has an inside anvil that sticks up and the priming mixture is crushed between the metal cover and that anvil. That FP tip looks like it could just be smashing the whole mechanism. Maybe that's it? When the gun is pointed down, any headspace, normal or excessive is enough to really mess up ignition? Kind of a "stacking tolerance" thing? The tip looks like what I was talking about when I said to look at the tip under a lens. It looks like a beat up, chewed up piece of metal. Funny how they look normal at first glance.
Consider that when these guns were run through their 6,000 round tests, all of them had increased headspace, but some were just cleaned and released for issue. So, maybe excessive headspace isn't such a problem in these carbines? I used to wonder how a long case could blow them up, but a case that is too short is OK? If they headspace on the case mouth with a short case, there should be a lot of headspace, but that extractor holds them against the bolt. In which case, extractor movement becomes critical.
I agree that it would be pretty hard to rupture a case in a carbine. The case is fully supported and I think it will stop shooting if head space got too long.
I have some experience with that. I picked-up a pristine Iver Johnson once that spaced at 1.311 but would fire maybe every third time. Primers would back-out on anything that fired. I came up with a bolt to pull the space back in to 1.305 and it shot ever since and was still shooting when I sold it. So, I think the action will continue to safely fire out to at least 1.305-1.306 and maybe a little longer, but it does depend on the firing pin protrusion and brass length also. Head space is the distance from the cartridge base and the bolt face. SAAMI allows a max of .022, which is pretty sloppy. One could use longer cases and keep the space within .022 and be in spec. if the headspace was long.
I hope we are not drifting OP’s thread too far, but most of this is pertinent to the case I think.
I had a few firing pins in the bin and picked up a bolt just to measure protrusion variations in a particular bolt. I took an I-I, RI and an RI c and measured protrusion of each. It ranged from .055 to .065 among these three pins. .010 can make a huge difference in whether a carbine will fire or not, especially if it is a little long on head space, or the brass is on the short end of spec. All firing pins are not created equal.
"I hope we are not drifting OP’s thread too far, "
sorry for my ignorance, but what does OP mean?
Original poster, the person that started the threadQuote:
Originally Posted by donki1967
gentlemen,
for the moment I can not go further in my tests following your precious advice.
I'm trying to find the bolt removal tool and longer cases.
Thank you, I'll get back as soon as possible.
Happy July 4th Celebration.
donki
Ten days till Bastille Day! Get ready to Celebrate.
That primer is really backed out.:confused: Get someones FIELD gauge for an M1 carbine and see if the rifle closes down on a FIELD gauge. :sos:
see
M1 Carbine headspace - CMP Forums
M1 Carbine Headspacing*** - YouTube
M1CarbinesInc.com
I might have missed this in the 5 pages, but does your bolt fire original military ammo OK? Have you tried original ammo not reloads???? Opps I see you are in France. Might be hard to locate a FIELD gauge and original ammo--bummer. I have the same problem with original French headspace gauges for my Mas 36 and 49/56.
I was having same issue with mine before i was advice to get a new factory case .
This has gotten silly. 45 posts over what is pretty clearly an ammunition problem created by handholds. I'll bet it would go away with factory ammo.
No special tool is needed to disassemble the bolt; a twist with a screwdriver is all that's necessary to pry out the extractor; the firing pin and all the other bolt parts will then come out.
Measuring headspace with gauges is a waste of time if the cartridge cases actually being used are not dimensioned within U.S. military specs. Too much headspace just produces misfires, but too little headspace can be dangerous. A cartridge case that is too long can prevent full rotation of the bolt, and induce insecure "toenail" locking. This will --sooner or later-- swage off the corners of the locking buttresses in the receiver, ruining the receiver, or --in more extreme scenario-- let the bolt open prematurely while pressure is still high and burst the cartridge case. If that happens, you will know it.
M
Consider this: These bolts are not Garand bolts, they may come apart like an M1 rifle but everything is smaller and more tender. Let's say that the OP tries what you suggest and the plunger goes flying and the spring breaks. Then where is he? "Too much headspace just produces misfires ", we know that, that's why there are 5 pages.... These things aren't just damaged with too long cases, they will blow up.
Hi,
My ordered RP cases arrived last week.
This morning I went to the range for testing a longer case length, namely trimmed to 1.284.
The shooting of my reloaded ammo went very well, no jam or misfire.
Good, sort of what we expected.Quote:
Originally Posted by donki1967
I’d agree with Mike that very early on, short cases were the issue here. The minimum case length is 1.280, but that assumes the action is not longer than a field gauge measurement and you can take your pick of gauge lengths from 1.299 to 1.302.
I think actual factual accurate head space measurements are very useful to determine the condition of the action. The OP might not even have to ever trim his brass as long as the case length doesn’t exceed his head space. 1.284 is not much longer than 1.280. Likely could guarantee better performance with longer case-lengths.
I am still waiting for someone to produce evidence of a ruptured spec-loaded carbine case due to long head space.
None have surfaced that I have heard about. The carbine chamber is completely supported and as long as the brass is spec…….very unlikely to experience a rupture. The carbine will very likely stop firing before a case would be exposed enough to cause a rupture due to long head space.
Probably won't go into battery so the bolt won't turn enough to fire. Unless it's very worn...Quote:
Originally Posted by flydthecat
Considering my reloaded ammo seems to work well in my carbine yet, and that I am in the safe dimensions of the cartridge, I will continue to do so.
Thank you to all.
Regards
The case length is so very important in the .30 carbine. The length of 1.280 has been around for a long time and in reality its too short. New factory ammo is set to the 1.285 length for proper head spacing of the cartridge. Trim to length is set about the same at 1.285. Trimming is mandatory with the carbine case and should never be longer then 1.290. If longer then a possible out off battery discharge can happen. The result is a destroyed bolt. The left side lug recess must be checked for damage too as a new bolt could be damaged by damage to the recess. But disregard the 1.280 case length.
Page 1, Post #2, The 1st reply which was by Floyd had answered the issue. Followed/Backed by BAR.Quote:
Originally Posted by flydthecat
Last 2 evenings, I measured the brass on 2 new boxes of S&B, Most every case measured 1.287". Longest were 3 that measured 1.288". Shortest were about 9 between 1.285" and 1.286".
Hats off to the members here. It's good to see so many chipped in and kept following to get the OP donki1967 up and running. It says a lot about the group here :thup:
To donki,
Do you remember back in July of 2014 when you were asking about the Rebuilt IBM in the NPM Hi-Wood stock with beautiful tiger stripe that a shop had for sale for $930.00.
To quote you: "The gunsmith is selling it for 930 $, prices are high in France"
That was 7 years ago now. Looking back, I bet you wish you'd of bought it considering what they bring today.
A link to refresh your memory or to give you that punched in the gut feeling: :banghead:
https://www.milsurps.com/showthread....151#post303151
Safe Weekend All,
Good morning,
Indeed I had the solution to my problem under my nose from the start and I made a mistake by not taking this info into account.
Nevertheless, these 54 contributions brought me a lot of knowledge about this rifle.
Best regards from France.
Just simple math. SAAMI specs. Allow 1.300 from the bolt-face to the cartridge base. That math’s out to 20 thousandths using the shortest spec. case of 1.280. Nothing other than that can be assured by design. If head space exceeds 1.300 and a cartridge of 1.280 in case length is loaded….no guarantee it’s going to fire by design. Sometimes it might depending on firing pin protrusion, but not designed to.
As long as one can keep the space below 20 thousandths, it’s suppose to fire and if the head space does not exceed 1.300 on any particular case length it should fire. Lengthening a case by .005 tightens head space by .005. If the action spaces at 1.302 on a case of 1.280 in length, you just reduced head space to 1.297 simply by lengthening the case.
I feel like many carbines are condemned for no reason at all and the fix is simply watch your brass and trim longer. Bruce is completely right…..stay away from 1.280 brass even if it is the spec. minimum.
A lot of carbine ammunition is actually too short to seat in the chamber as designed: chamber seats on the case rim at the front. So the cartridge is held by the extractor and fires that way. I ordered a quantity of Remington brass years ago. The case lengths were all over the place but none were too long (The dangerous exception). It all fired just fine as is. Which puts the lie to a lot of headspace enthusiasts.
I will purchase a carbine all day long that head spaces in excess of a field gauge, but I do have a limit. Some consider 1.301 and greater as junk…..those are the ones I will consider at a discount price (of course) after they have considered it defective. There is way too much forehead sweating, hand-wringing and barrel replacing over a action that might only exceed 1.300 by a couple thousandths.
Soldiers took this gun into battle and the powers-that-be wanted to make sure it worked on that short brass that could get out there, so they decided to condemn it on the safe side. It will shoot and be completely safe well past 1.300.