Hey all,
I just checked the headspace on my 1898 with Clymer go, no-go gauges and the bolt closed on both. Is there a fix for this? I have not fired this gun but would like to. Hope someone can help.
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Hey all,
I just checked the headspace on my 1898 with Clymer go, no-go gauges and the bolt closed on both. Is there a fix for this? I have not fired this gun but would like to. Hope someone can help.
Anyone?
Do you have access to another bolt? Maybe you’d get lucky and that’ll help.Quote:
Originally Posted by CHUCKW
Hang on a couple days, being the weekend...the usual suspects will see this and I'm sure you'll get more answers.Quote:
Originally Posted by CHUCKW
I have to ask though, have you shot it? Is there a problem? How does the brass look...
I have not fired it yet. I wanted to verify that the headspace was good first and it doesn't seem to be.Quote:
Originally Posted by browningautorifle
---------- Post added at 08:46 AM ---------- Previous post was at 08:46 AM ----------
I don't have another but could look online, I guess.Quote:
Originally Posted by rcathey
First of all, may we assume that you have inspected the bolt for any obvious signs of damage or excessive wear? If the bolt is OK, then maybe there is nothing wrong with your rifle at all.
Some explanation is in order here, but don't take anything I write on trust - others will have a different opinion.
The 30-40 US Krag is a rimmed bottle-neck cartridge.
The rim means that, even if the neck is set back very far (relative to the chamber) the cartridge cannot move forwards any more than permitted by the head/rim clearance, i.e. the space between the front of the rim and the bottom of the rim recess in the chamber.
Now the Krag was a cartridge introduced in the 1890s, like the .303 British. And like the .303 it was a military cartridge. Furthermore, it was about 30 years before SAAMI was set up, so using modern standards to judge something made decades before those standards were established is not fair on the items concerned.
Sticking my neck out a little here, I would guess that, just like the .303s and other military cartridges of that era, the Krags were made with a good chamber tolerance, and a "high" shoulder, so that the maximum tolerance cartridge would fit in the minimum tolerance chamber, even in a dirty chamber after the soldier had let a clip fall in the mud, wiped it off on his trousers, and then loaded it in the rifle. Type acceptance tests were made for the kind of worst case situation that might arise in battle. Benchrest tolerances were not envisaged!
And, don't forget, military cartridges were made to be used once only. My limited experience with .303s is that the neck, after firing, is noticeably further forwards than on a freshly resized case. No problem with once-only use, and better than a high case shoulder possibly impeding loading of the case, with potential slam-fire problems when the bolt had to be banged shut. Or a rifle put out of action because the case was hopelessly jammed. - Battle rifles had to function in tough conditions.
In other words, that fact that you can chamber a no-go gauge made to modern standards does not prove much more than that you can chamber a no-go gauge made to modern standards. So what?
There is quite possibly nothing wrong with your rifle at all. I understand that you are concerned about possible safety problems, so I suggest that you measure the head/rim clearance, which I described only last week in answer to a similar query. Please look it up.
Since a rimmed case is held back by the rim, regardless of any clearance between the shoulder on the case and the shoulder in the chamber, about the worst that can happen on firing is that the case will be stretched as the shoulder moved forwards to match the chamber. This is the major reason why it is not good to fully resize cases on old milsurps in general. Fully resizing will lead to an early case failure, typically about 1/2" above the base.
So measure the head/rim clearance, as described elsewhere. It is likely to be in the range 10-30 thousandths of an inch. Much more than that, and the gun may fail to fire, because the firing pin fails to detonate the primer. Check the bolt, chamber etc for sign of damage. Then you can fire a test round. Measure the position of the shoulder after firing and compare it with an unfired case. You may well be surprised at the difference.
The trouble with headspace gauges, in my view, is that they may provide a false sense of security. While it is true to say that the use of a headspace gauge can point out a potential safety problem, such as battered bolt lugs, that needs to be investigated, the reverse - that a "pass" using headspace gauges proves that the rifle is safe to fire - is not true.
Finally, gauge sets should have a "go" gauge, a "no-go" gauge, and finally a "field" gauge. I have suggested above, that military rifles will frequently accept a "no-go" gauge, because of the combination of initial manufacturing tolerances and a century or more of wear. But a failure with a "field" gauge (i.e beyond that acceptable for a active service rifle) would be a more serious indication that something is wrong.
I use a 'knock-off' .30-40 Field Gauge that measures .073". None of my Krags will close on this. (I strip the bolt for testing).
Amazingly, my fired Brass Cases will fit, (without re-sizing), eight different Krag rifles and carbines.
I do have a model 1896 rifle that has a larger diameter chamber. The head-space is OK, but, fired cases are expanded more in diameter, so they will not chamber in my other Krags without Full-Length re-sizing. (I segregate Brass fired in this rifle and just Neck-Size it).
For my other Krags, I also just 'Neck-Size' my Brass, when reloading. (I don't have to keep the Brass separated by rifle).
I have also answered OP's question on Krag Collector's Association Forum.
So again I ask. Maybe he should fire it and see if there's a problem? I'm not talking out of my a$$ after all, I've had these too...
'CHUCKW' can add a thin washer or layers of foil to his 'No-Go' head-space gauge, to build up rim thickness to .070 to .073". This will allow it to serve as a 'Field' gauge, for repeat testing.
Should his bolt close on this impromptu 'Field' gauge, a NOS model 1898 bolt can be bought on ebay for $55.
Thanks to everyone for their replies. I will re=read them all and consider my way forward. I am feeling more confident about my Krag now but will be cautious.
Let us know how this works out...
As alluded to in earlier posts, the Go and NoGo gauges are used when installing a barrel. To check if rifle is still "within spec", then one uses a Field gauge, which is longer than the NoGo gauge. I have no experience with the Krags, but I believe the "Field" gauge, either pass or fail, is the "test" for whether a rifle's headspace is "safe" for continued use or not. British, American, Russian, German, etc. If it fails, then investigate why (Receiver lugs set back? Bolt lugs worn? Chamber worn or stretched) and respond accordingly. Several of these issues mean the receiver, bolt, or barrel, or all of them, are trash.
It use to be a practice among some professional and amateur gunsmiths to 'Lap' the rear of the single lug on the U.S. Krag Bolt.
The intention was to allow the rear of the Bolt's 'Safety/Guide Rib' to make contact with the receiver, when the Bolt was closed.
(Danish and Norwegian Krag rifles were manufactured to have this 'rib' contact. U.S. Krag Bolts had a few 1/1000" clearance).
IMHO - This 'Lapping' may have made the U.S. action slightly stronger, but, it also likely introduced more 'head-space' or 'free-travel'.
Agreed, opens up the headspace.Quote:
Originally Posted by butlersrangers
IMHO - A U.S. Krag bolt should show some clearance, (approximately .001" to .004"), between the rear of the Bolt's 'guide rib/ safety-lug' and the receiver. This appears to be how Springfield Armory built them.
If the rear of the 'Safety Lug' bears against the receiver, it is likely there is locking-lug wear, 'lapping' of locking-lug, or 'movement of metal'.
Head-space should be checked with a Field Gauge.
Attachment 102891
If you are a handloader you could always load some fire forming rounds by loading a bullet in the lands of the rifling to hold the case against the bolt face and then fire form. These cases would then be for this rifle only and would require neck sizing only.
Ken
Can also be achieved the way .303 guys do it...use a tiny rubber "O" ring around the case at the base. Holds the base against the bolt face and then neck size...Quote:
Originally Posted by skeet1
Jim,
I had forgotten about the "O" ring trick. You are right , that would work very well!
Ken
"Last On 10-10-2019 @ 03:36 PM"
He didn't tell us if all worked out or not...
Headspace 101 for .303's
Several generations of American shooters have been convinced by bad information that something mysterious and scary called "headspace" should be checked and re-checked on almost any surplus rifle, especially Lee-Enfields. The truth is less interesting but still worth knowing.
Stripped to its essentials, with a rimmed cartridge like the .303, headspace is simply the distance between the front of the bolt and the back of the barrel. It's the space where the "head" (rim) of the cartridge fits when the rifle is loaded.
Since there has to be some room to allow for varying rim thickness, the headspace is normally a bit more than necessary - giving what I call "head clearance", a little extra space so the bolt can close easily, even on the thickest rim allowed.
In addition, Lee-Enfields and their ammo were often made with a fair amount of space for dirt, mud, snow and other battlefield debris between the chamber and the cartridge's body and shoulder ("Body/shoulder clearance"). Since the cartridge is controlled by its rim, this clearance doesn't do any harm (except to handloaders who insist on full-length sizing).
When a full-power .303 cartridge is fired, a whole string of events occurs.
1. The firing pin shoves the case forward, rim against the breech. 2. The primer detonates. If it's not heavily crimped in place, it backs out, shoving the bolt and barrel as far apart as it can. 3. The thin, forward part of the case expands to fill and grip the chamber while the bullet moves out of the case and down the barrel. 4. The solid case head can't expand and grip the chamber, so it moves rearward, re-seating the primer, stretching the case walls just forward of the head, and stopping when it hits the bolt face. (In rear-locking actions like the Lee, the bolt and receiver also compress/stretch to add a little more movement. The higher the pressure, the more they move.) 5. If (and only if) the amount of head movement exceeds the elastic limits of the case, the cartridge separates into two pieces.
New cartridge cases can normally stretch a lot before breaking. Even with a minimum rim .054" thick and maximum "field" headspace of .074", the resultant .020" head clearance is well within the limits of new brass and it's very unlikely a new case will separate even if the headspace is somewhat more than the field maximum (which is pretty rare).
OK, but if one does separate I'm in deep trouble, right? Not really. It seems the short "cup" left behind the break is pretty good at keeping most of the gas where it belongs. Here's a demonstration -
First I took a case that had been reloaded with heavy loads enough times so it was stretched near breaking.
I loaded it with a 180-grain bullet and 40 grains of 4895 - a reasonably stiff charge about 2 grains under "maximum" - and fired it in a much-abused Savage No.4 with a clean sheet of typing paper wrapped around the receiver.
When I opened the bolt, the separated head extracted. (The front piece of the case fell out when I happened to turn the rifle muzzle-up while removing the paper.)
The sooty paper shows where some gas escaped. No rips or holes, just a little soot - and only where the bolt meets the barrel. Had I been shooting from the shoulder and wearing glasses, I probably wouldn't have noticed the leak at all.
The point of all this is that excess headspace, even a bit beyond normal limits, isn't the terrible danger we've heard so much about. It's not a good thing for consistent ignition or long case life (although handloaders who neck-size or adjust F.L. dies carefully can control this) - but it's not a disaster waiting to happen.
Unless you're consistently getting broken cases when firing new ammo or brass, there's not much reason to be worried about headspace in these sturdy old Lee-Enfields. Relax and enjoy!
Handloading
If you handload, there's no need to mess with bolt heads - changing the rifle's clearances to yield longer case life. You can control head clearance simply by changing technique.
When you fire a new case for the first time, use a moderate powder charge and put a thin film of sizing lube on the case. This inhibits the case walls from gripping the chamber and eliminates or reduces stretch even if head clearance is significant. Another way of accomplishing the same end is to use a bullet seated out far enough to jam into the lands, "headspacing" on the bullet instead of the case.
After you've fire-formed your new cases they will fill the chamber fully, headspacing on the shoulder just like a rimless cartridge. If you neck size, you'll have zero "headspace". If you have to full length size, adjust the die so the cases chamber with just a bit of resistance in the last few degrees of bolt rotation.
Finally, don't try to turn a .303 into a magnum. Keep the pressures below the limit and you reduce the small amount the bolt and receiver compress/stretch on firing in a rear-locking action.
With these techniques you can make your .303 cases last for dozens of loading cycles, even if your "gauge headspace" is well beyond the .074" field spec.
Observations:
G'Day Pat, a great response, overall. As an Enfielditis carrier (I don't suffer from it... I breed it) I concur with your assertions of how the .303 case changes. Dramatically, in many perfectly serviceable rifles.Quote:
Originally Posted by Patrick Chadwick
I would like to, politely and gently disagree with you on one of your points.
Your last paragraph is generally agreeable, but the 'Field' gauge, I suggest, with all due respect is another modern invention, as are SAAMI specs, which do not bear accurate resemblance to the original Military or Government Supply specifications of the various calibers they purport to represent. Note, with respect to the Yanks, that the Association that agreed on what they would make is entirely composed of United States firearms and ammunition manufacturers. For the thinking person, that fact alone should cause concern.
Let's take the .303, which I am intimately familiar with, about 25 units over... The Service specification for the head space, as per Instructions to Armourers and what Peter Laidler continually cites is: GO = 0.064" NOGO = 0.074"
That's it.
No 'Field' gauge - which is a fabricated range legend. Now for the argumentative types, please refrain from "but, but, what about the Vicker's MG gauge?..." Not relevant. We're specifically talking about the tolerance on a standard Service Rifle with standard Ball ammo.
The 0.067" (or sometimes cited as 0.068") gauge that crept into modern legend came from the Civilian Target Shooting fraternity, you know, the Bisley types. These fellows were dedicated to eliminating as many variables from their shooting to ensure highest possible repeatable score. One of the things they did, was to measure the thickness of the rims of their Service Issued (well, sourced) cartridges and group them in lots of thou increments. The idea here was consistency within serials (series of 10 or 11 scoring shots.) Having all the same dimension cartridge rim, there would be minimal head space difference causing changes in shot placement. So, this very particular and fastidious behavior crept into other areas. The smaller head space range than what the Service specifications set, became accepted within that group of shooters. What never changed because of the target shooter's fastidious decrease in tolerance, was the acceptance range of a serviceable .303 head space - still 0.064" to 0.074".
Now what I do agree with Pat on, is the adoption of good and unacceptable limits. In the Krag (which is very similar to the .303) there was always a Service Specification of acceptable head space range from a low number to a higher number. Any other intermediate datum you wish to put in between does not change the "GO" and "NOGO" limits of Service specification. Field, whether people like it or not, is a modern construct not included in any Commonwealth (and I suspect US TM- ) doctrine. If you choose to use the upper serviceability headspace tolerance figure as your "Field" then I concur that that's a safe way to present your expectations in public, because it indicates you're choosing a lower limit for your 'NOGO' tolerance. That is safe.
To round out, let's be clear that the NOGO head space was not an indication of absolute safety. It was a limit of practicality and most importantly, reliability. Can a rifle with oversize (out of tolerance) head space work safely? The answer is probably yes, most often. Is it reliable? Most probably not very. Will the cases be suitable for reloading several times? Maybe, maybe not... Patrick is absolutely spot on in drawing your attention to headspace alone as no means of determining the safety of a rifle body/action (I'll not go into the ongoing discussion about what to call the receiver group!)
I hope this comment helps and does spark some thought among a few, at least. Thank you for reading.
I would fire form some cases blowing the shoulder forward and then reload as normal being carful not to push the shoulder back where it was.
Ken
Sorry to stick my oar in, so late in the discussion, but nobody asked if the locking lug of the bolt had been checked to see if there was any crack evident between the locking lug and the bolt. This was a single locking lug action, and had a reputation for extreme smoothness, but not great strength. It was not uncommon for a gunsmith to lap the locking lug so that the safety lug/guide would rest against the receiver to strengthen the action when a sporter was being built. The headspace would be adjusted accordingly. I wouldn't expect this modification in an unaltered firearm. Without magna-fluxing the bolt, the usual method to look for cracks in a receiver or bolt was to wipe it down with a gasoline soaked rag. The gasoline would evaporate off the body, but would still be evident in any crack.
As an aside, isn't the field gauge for the 30-40 Krag and 303 British the same?