Factory cartridge primers protruding after firing

Sounds like excessive head space to me. If you hand load you could try headspacing on the shoulder.

Is always possible that the bolt has been replaced resulting in excessive space from the cartridge case to the bolt face. Needs to be checked before something bad happens.

Its low pressure that causes it, not high pressure.

Every primer backs out of every round when it it fired.
Then, pressure stretches or slips the case back tightly against the bolt face and re-seats the primer.

If there isn't enough pressure to stretch the case, or the chamber is too rough to allow the case to slip back, the primer will remain backed out.

Lever-actions have rear locking lugs, and as a result are very stretchy actions.
It's not that unusual to see protruding primers with them.

It may be excess headspace, but that would usually manifest itself in stretch rings inside the fired cases, and in the extreme, broken cases with the head and about a 1/2" of case ejecting, and the rest of the case stuck in the chamber.

rc

+1, agree with rcmodel completely

My 1964 Win94 does the same thing and it was essentially NIB when I got it. Unless Winchester was shipping them routinely with excessive headspace, I agree with the posts above it is just weak ammo.

I fixed my problem by headspacing on the shoulder like most bottlenecked rifles and then worked up toward the max load for the round in the current load manuals. Between these two steps the problem went away.

My 1967 (mail ordered from Herters) Marlin 336 in 30-30 does the same thing with factory loads. Reloads don't show the same problem.

As usual rcmodel has hit the nail squarely on the head...........IMO

rcmodel, these guys do not make it easy to suggest there could be other things going on but the case being locked down in the chamber by dirt, grit and grime will have the same effect as ball bearings (sorta), in the perfect world the maximum case hold between the two surfaces, case and chamber is obtained by a mirror finish with 100% contact between the two, it is a psi thing.

Then there is that primer thing, I do not agree with the logic as to how the case got up front and the primer got shoved tword the rear, then there is that part where the bullet, powder, case and primer can excellerate to a speed that would allow the cartrtridge to out run the firing pin and avoid a primer strike.

F. Guffey

rcmodel said:

Its low pressure that causes it, not high pressure.

Every primer backs out of every round when it it fired.
Then, pressure stretches or slips the case back tightly against the bolt face and re-seats the primer.

If there isn't enough pressure to stretch the case, or the chamber is too rough to allow the case to slip back, the primer will remain backed out.

Lever-actions have rear locking lugs, and as a result are very stretchy actions.
It's not that unusual to see protruding primers with them.

It may be excess headspace, but that would usually manifest itself in stretch rings inside the fired cases, and in the extreme, broken cases with the head and about a 1/2" of case ejecting, and the rest of the case stuck in the chamber.

rc

Click to expand...

Yep.

When I read the title of this thread, I said to myself "I bet he's got a 30-30.".

I have seen this on a couple of 30-30s. I even bought a NOGO headspace gauge, but neither gun would close on it.

It is strange because over the years I've seen some 30-30 do this while many do not. Seems like I've seen more 94s do this than 336s for some reason. Could be a case of stacking tolerance I suppose.

One thing you may try right before shooting is to degrease the chamber. Clean the oil out of the chamber with some alcohol. It will help the cartridge case stick to the chamber the way that it should when it fires. This will decrease bolt thrust.

No, 1/8 = .125 thousands, it is not possible for the primer to protrude from the rear of the case 125, I would suggest measuring the protrusion of the primer with a depth gage first.

There must be a very serious problem with the bolt, bolt face, lugs or bolt seating surface to have 1/8 inch head space on a Model 94, in the perfect world the Model 94 would have .005 thousands head space, it would not be unusual for the 94 to have .008 thousands head space. The problem with the protruding primers (primers not seating) when fired is not normal because of the tapered case. Check the face of the bolt to determine if it is cratered.

I have a Model 94 without the problems mentioned above, if I had excessive head space and wanted to head space on the shoulder I would neck the cases up to 338 then size the neck back to .308 with a .020 gap between the top of the shell holder and bottom of the die, if after sizing the neck with the .020 gap the case did not chamber I would then reduce the tap to .015 and then check for chambering, I would continue decreasing the gap until the case would chamber.

Remember, the .30/30 head spaces on the rim, not the shoulder, the bolt face would be bent on the edge or the extractor could prevent the case from seating on the bolt face, I am assuming the rifle is a 30/30.

F. Guffey

If you handload you can try seating your bullets a tad long to ensure the case head is shoved up against the breech block. This will mitigate protruding primers and stretched out cases. Then just adjust your dies so that your not squashing the shoulder back to the original cartridge length. It's a band aid fix for a bigger problem but it will work and doesn't hurt/increase the risk of anything. The real rub becomes if you ever pass the rifle off to someone else. . .

I'm confused about a couple things.

If the case isn't setting back against the bolt when fired, how will setting the size die out help, the case isnt expanding into the available space (not getting longer, shoulder not setting forward)? That should only work if the case is setting back against the bolt face, which the protruding primers is a sign that it is not doing.

Having had a number of 94's over time, its a fairly common thing to have happen. It doesn't mean the headspace is grossly out of spec, it's a low pressure symptom (try firing a few cases with primers only in your favorite revolver). There has to be some clearance, and your ammo may add to that. Things that may be an issue in other types and cartridge, simply don't cause problems in these actions. Ackley did some fooling around with 94's, and came up with some interesting conclusions. He went so far as to fire one with the barrel turned out up to several turns, and other than the primer backing out, it did no harm. He also fired it with the locking bolt taken completely out, and it had no troubles, the case stayed in the chamber, and the bolt stayed in place. There just isnt much bolt thrust in the cartridge and action. Basically, if the case is staying in the forward position in it's available space, the slight clearance isnt causing a problem. The case is sticking to the chamber walls. It isnt going to cause case separations (or hasn't for me in the 30 some years I've been using my pile of brass, in various 94's that back primers out a little, or for anyone else that I've heard of so far). Excessive headspace with the case setting back against the bolt face would cause problems with case separations. It just doesnt seem to happen with the guns I've been shooting. I've gone to the point of having the rear of a bolt welded to build it up, and hand filing it to get absolute minumum clearance to close the bolt on a case. First shot, the primer was backed out a touch, and hasnt ever changed since. I quit worrying about it, it simply doesnt seem to cause any troubles. I've shot hundreds of rounds thru that one and the various other guns and never had trouble with cases. Theory in 50,000 cup or psi loads is one thing, and may be a problem in a 308 bolt gun, actual practice in use in the 94 is that many of them back primers put a little, but it only seems to annoy some people but do no harm.


Protruding primers and stretched out cases are opposite effects in this situation. So far, I haven't heard of anyone having both symptoms at the same time in a 94. I also don't think the action is as "springy" as is commonly believed, so long as it's used in the common calibers this action was built for.

Have the gunsmith polish the chamber.

rc

The cases "sticking" to the chamber walls isnt bad, thats exactly what the case is supposed to do, and one of the reasons for some Ackley modifications. Your chamber may be a bit rough if its marking cases, but I don't see it as a problem unless it's actually damaging them.

I'm curious as to what your gunsmith says. You no doubt noticed the post above where natman tried the headspace gauge, and it was in spec? If your guy says it's in spec, but wants to go to heroic measures to "correct" it, I'd ask if the work is free if the primers still back out afterward. What I'm saying is, this is a misunderstood thing to many, and, as natman and others have indicated, the gun can be in spec and still back primers out some. It simply isnt a disatrous problem as some seem to feel. 30-30 cases are thinner than most rifle cases, the cases adhere to the chamber walls rather well at the lower chamber pressure of the round. There has to be some headspace clearance (which is exactly what "headspace" is, the required space for the cartridge to chamber properly, and within set specs) for the cartridge to chamber, and to allow for variances in difference cases. You can polish the chamber and make the primer thing go away, but you are also causing more bolt thrust. It isnt likely to cause a problem, but that's just what the result is. You can oil the case and get the same result, but that isnt recomended. Ackley did it to make a point. The primers reseated, but the cases function properly when they adhere to the chamber wall enough to contain the pressure, but not stick when extracting.


To put it another way, the very fact that the cases are adhering to the chamber wall, and the primer is backing out a little, means the case is functioning properly. That there's is a small amount of room for it (the primer) to move isnt a problem, it can be within headspace specs and still do this.


FWIW, Winchester used to make various sizes of locking bolts. I have examples in +.005", .010", and I believe .15" oversize. They are marked on the bolts. I've picked them up at gun shows from parts guys, usually paying $10 to $15 each for them. After the little adventure with building up the rear of the bolt on the one rifle, I quit worrying about it. I figured that if I had a rifle that had more than average primer protrusion, and showed true excessive headspace clearance, I'd deal with it with one of the oversize locking bolts. Until then, I'm not worrying about the small amount of protrusion that about half of my 94's show. If your guy says that your gun is within spec, or even if its out, you may want to try finding an oversize locking bolt. This is something you can do yourself if you know how much room you need to deal with.

Here's a pic of oversize locking bolts.




"...I'd hate to lose this externally pristine example, but my confidence in the gun is shaken, and I'm not clear I could ever get over the concern every time I tickled the trigger, unless it can be fixed.... I'm obviously not mentally built like you Malamute!"

No reason to "lose" it. If the gun is within spec, enjoy it. I carry a couple of mine walking along the edge of the mountains. There's large, sharp edged critters there (Grizzlies and Mt Lions). A 30-30 isnt a bear gun, but I have absolutely no qualms about the reliability or safety of my Winchesters.

This was an absolutley thrashed 1927 carbine. I cleaned it up, it looked like it hadnt been cleaned in any way in 50 years of hard use, and have used it regularly since. It's the one that I built up the bolt on to minumum clearance to be able to close on a case, only to still have the primers back out a little. It functions perfectly.



Another misunderstood thing about Winchesters. If, or when they have problems, they don't "blow up" like bolt guns have at times when they have catastrophic problems. So far as I know, when Winchesters "let go" its always been a barrel that goes, not the action. I've never heard of, or seen a pic of an action that let go. The receiver may be damaged, but it's the barrel that starts the festivities (similar to the fact that revolvers cylinders let go long before a frame does, if the frame went, it was started by the cylinder). The bolt doesn't come back in your face, as some assume. One guy rebarreled various lever actions to 454 Cassull to see what they would take. Of the several Winchester 94's and a Marlin 336, he tried, none "blew up", tho they did stretch the action to the point of being unsuable, as in, simply wouldnt function. This happened in from 20 to 50 rounds of 454 Cassull. If anyones interested, the Marlin 336 failed sooner the Winchester 94's did. The Marlin receiver walls bulged outwards from the locking bolt trying to move backwards. The Winchesters stretched the sidewalls of the receiver visibly, particularly the angle eject gun tried. Either will last a lifetime of hard use when used with the standard rounds the guns were made in, even with some slop in the action. If anything happens to them other than a catastrophic barrel failure, they will simply get so loose they stop functioning. I've never seen one that loose in the many hundreds of 94's I've seen.

It's a standard band that I drilled and inlet a knurled nut into the wood underneath it. I used to just tap the band for the stud, but it only had about 1 1/2 threads. Never had one pull out but it didnt look real strong if you put much stress on it. I've heard that Marlin bands will work, but I havent tried them. The Marlin bands come with a stud now.


The carbine had been a ranch gun somewhere in Az. The outside of the gun didnt get much attention, other than the fact that the buttstock was so trashed I threw it away, and put a stock on it that someone else was going to throw away. The magazine tube was damaged and cut shorter, so I got a new mag tube. Had a surprise when I took the tube apart. The spring was worn through in 2 places. Someone in the distant past had overlapped the ends of the spring and wrapped thread around them, and called it good. It still worked. I went ahead and sprung for the big bucks and replaced the spring. The action felt like it was full of mud, it was so cruddy. It still functioned tho. I took it completely apart and soaked it in a bucket of carb cleaner for a month, then brushed it clean and put it together. That was about 25 years ago. I havent felt any need to take it apart again. I can keep it clean enough with the action open and a toothbrush with some solvent. It cycles crisply, and functions perfectly. The bore was real rough, but it shot about 4"-5" groups. I had it cut 1/8" and recrowned and it went down to about 2 1/2" @ 100 yds. Good enough. It came with a Lyman No 56 sight on it also. Today, those sell for more than I paid for several of my 94's. My only regret is that I didnt buy the other carbine that came from the same ranch when I bought this one. They were $75 each.

This gun now has a spare barrel that I had cut to 16", as the picture shows. Makes a dandy truck gun.

Don't forget that the whole headspace thing in rifles is because ammunition cannot feasibly be made perfect. In theory (and at considerable cost), all rifles could be made to an exact headspace. But if ammunition were not similarly controlled (and it cannot be as a practical matter), some rounds would have a gap and others would not chamber. That is why there are GO and NO-GO gauges for rifles, so that any ammunition that is within established tolerances will work.

So, one brand or box or even cartridge may work fine and another show signs of headspace. At ammunition factories, the cases from several production lines (with different drawing dies and different head forming dies) are dumped into the same bin, then on to loading and boxing, maybe again on different lines. So the cases in a box might not all have been made on the same equipment, and that equipment also has been made to tolerances.

Jim

That suggest we could be hearing, seeing and or reading the same thing/event and afterwords have different opinions of what was read, seen and or heard.

Ackley demonstrated the advantage of the 30/30 Ackley Improved chamber, removing the taper of the case decreased the thrust, to demonstrate the effectiveness of a case with little tapper he removed the bolt lugs, the best thing that ever happened to the 30/30 Winchester, 30/40 Krag, 303 British 300 H&H and 257 Roberts was P.O. Ackley. He established a shoulder and removed most of the tapper on chambers that were cut with little consideration given to how the case body and shoulder fit the chamber, the case was held back in the rear to allow the body of the case to fill the chamber, out and forward.

4 of the 5 cases listed above can head space on the rim and or belt, or on the shoulder, it is not easy to head space on both, for most before the case can be sized to head space on the shoulder the case must be fired first, those that form cases first and then fire determine the effect the case has on head space first, others fire first then determine the effect the chamber had on the case.

Again, there is that part where the case, powder primer and bullet (cartridge) can accelerate to a speed that that allows it to escape the impact of the firing pin, then the part where the firing pin pushes all of that weight forward before the firing pin crushes the primer, in my rifles the firing pin crushes the primer before the cartridge knows it has been hit, so the difference, before anything happens the primer is crushed by the firing pin and for the lack of a better word or group of words the firing pin has a travel limiter, I personally do not care what happens next as to how the case gets shoved forward but with a travel limiter on my firing pins and my primers absorbing the impact before the case can move AND the primer when lit burns fast with no room to expand my cases are blown forward by the expanding gases, psi being equal in all directions pushes the case forward and the primer to the rear (in my rifles), then the slower burning powder is ignited and rapidly expands causing the case to expand and lock onto the chamber.

Then we come to THIS 30/30, not my 30/30, THIS 30/30, The firing pin is striking the primer, the primer is igniting, the case is pushed forward, in my rifle by the expanding gas in the primer, in all the rest of the rifles the case is pushed forward with the firing pin, then the case locks onto the chamber, then comes the difference between My 30/30 and THIS 30/30, the head of the case is not being pushed back against the bolt face meaning there is not enough pressure in the case to stretch the case between the case head and body of the case, If the primer is not being re-seated after unseating itself the pressure for what ever reason is too low

Size a few cases then install primers, without powder/bullet, chamber and fire (case will be driven forward, the primer will be blown back), after firing eject the cases, cases with protruding primers will either demonstrate the effect the firing pin had on case travel or the effectiveness of the primer to separate itself from the case, slow burning powder with a worn barrel can be a contributing factor, bullets that are too small in diameter for the bore can also be a contributing factor.

F. Guffey

Interesting that you posted this. I've been thinking about the difference between the Winchesters, that seem to more often show slightly protruding primers, even when the headspace is in spec, and the Marlins.


Guffey makes a good observation, tho I will suggest that the part regarding the firing pin moving the cartridge forward (or not) upon firing, does not apply to the Winchester 94. I believe that may be why the Winchesters often show the primer protrusion and Marlins do not. It isn't that the Marlins are "better" or the Winchesters "not as good". The two points come together thus. The Winchester 94 has a fairly substantial ejector spring that always bears on the cartridge, holding it in the forward postition upon firing. The Marlin does not have such a spring providing a "preload" on the cartridge. The headspace specs may be identical, but the evidence, or result of firing the same cartridges in the different guns becomes apparent. Marlins tend to have slightly tighter chambers in my experience as well, tho I think this isnt so much a factor in this particular situation regarding the primer protrusion and headspace spec.

Again, we come back to the somewhat unique situation of a rifle cartridge of modest chamber pressure, relatively thin case walls that adhere fairly well to the chamber, and not much bolt thrust as a result of the combination of factors. The point about Ackleys tinkering with the improved chamber is correct, tho in the instance we are considering, I believe the standard case is behaving in a similar way with standard level loads. The result seems to be the same in the circumstances we are discussing. The primer is not reseating when fired, even with headspace in spec. It isnt a "gun about to explode in a nuclear catastrophy from dangerous headspace problems", it's a benign quirk of the combination of factors present in that particular combination of cartridge and action. The 94 action seems to be entirely capable of dealing with whatever the 30-30 cartridge pressure can produce, without anything catastrophic happening. As was mentioned, they have been tested to destruction with a 60-65kpsi round, and simply became unusable (unfireable) without coming unglued. In the standard round, they will go a long long time of hard use without anything dramatic happening, even if they do ever happen get out of spec.

I believe a load can be made that will overcome the balance point of primers reseating or not, as Peter Eick has suggested. It shouldnt hurt anything to do so, but I would guess that the cases probably do not last quite as long when that level is reached unless the case isn't full length sized. If full length sized with the die all the way down on the shell holder, it will likely use up the cases sooner. Most factory rounds seem to be slightly below that point of reseating primers, as have many "standard level" handloads. The factor of case dimensions varying is likely a factor in how much primer protrusion is noticed as well. I haven't checked case rim thickness to see how much variance they have. Your headspace needs to have enough room to accomodate any cartridge that is made within standard dimensions. Not all cases will be maximum dimension, thus room for the primer to move back upon firing.

Remington 30-30 bullets tend to be about a thousandth smaller diameter (.307" diameter) than most others in this caliber. It would tend to reduce chamber pressure. I dont think thats a bad thing, so long as they shoot well in your gun. I also don't think loads that don't reseat primers in a 94 are bad. The gun and cases will likely last a long long time at that level. That has been my experience over time, tho I havent considered all the reasons why until recently. So far, I've never had a case head separation in a 94, or evidence of an incipient separation.