Whats going on with my Jungle Carbine?

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Roamin_Wade

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Took my son to the range on Xmas eve. He's been wanting to shoot that Enfield so it went with us. As I was putting the brass into the box, I noticed that about 5 of the 20 had through holes in the primer. I thought back about shooting it and I could swear I felt on my face, on a couple of shots, like the percussion of the rifle had kicked up some sand or something and pelted my face with it. I'm wondering now if that was chamber pressure pushing through some sort of gas check valve. Can someone tell me what may be going on? Could the firing pin be too long? I wouldn't think so as I've shot this rifle before and the primers weren't through-holed. Bad ammo? Is there a gas check in that rifle?
Thanks for the help and advice...
 
it is either excessive firing pin protrusion - or very soft primers.
is this the first time it has done this?
try a different brand of ammo and see what happens.

I will look at the spent casings I have when I get home to see if any are through-holed. I want to believe this is a new problem, whatever the problem is. One thing has changed and that is the buggered up original stock has been changed to a new synthetic Monte Carlo stock which was made for a No.4 but with some inletting, fits great on the JC. (I'm not a fan of synthetic stocks at all but the wood furniture that was on it was trash. They had dug out the forearm piece, I guess to glass bed it but they went too far. It was slapping around up there completely loose.)
 
There are no pressure release/blow ofd valves in any firearm IM aware of....well besides atmospheric venting on some semi auto systems.....and maybe barrel porting/brakes, depending....

Same questions, handloads, old facotry, or new factory.
If all you experienced was popped primers, with no other signs of pressure (bolt stick, flattening, brass flow etc) here's what what id do.

using handloads, I'd take down that batch and check to see if there are any obvious issues with the loads. One thing that MAYBE an issue is if you accidentally used LPPs instead of LRPs for instance.

If it was old factory, I'd try fresh factory ammo.

If fresh factory ammo, I'd try another brand.

those are just the steps I'd try. I'm not horribly familiar with the enfields, so perhaps someone who is will have a better take on it


oopps missed the post.on factory ammo. What brand were you shooting?
 
I'm too lazy to look into it but I thought I recall the enfield having an adjustable firing pin protrusion. I would check that and also be aware that an overpressure round can cause pierced primers. I have had that happen before.

The facing piece that the round abuts back on is threaded but if I were to unscrew it one turn, the thread pitch is so that the firing pin wouldn't protrude enough, I believe, but I will reassure that theory this evening. Does the bolt contain a pressure check?
 
There are no pressure release/blow ofd valves in any firearm IM aware of....well besides atmospheric venting on some semi auto systems.....and maybe barrel porting/brakes, depending....

Same questions, handloads, old facotry, or new factory.
If all you experienced was popped primers, with no other signs of pressure (bolt stick, flattening, brass flow etc) here's what what id do.

using handloads, I'd take down that batch and check to see if there are any obvious issues with the loads. One thing that MAYBE an issue is if you accidentally used LPPs instead of LRPs for instance.

If it was old factory, I'd try fresh factory ammo.

If fresh factory ammo, I'd try another brand.

those are just the steps I'd try. I'm not horribly familiar with the enfields, so perhaps someone who is will have a better take on it


oopps missed the post.on factory ammo. What brand were you shooting?

It was Remington lead tipped, round nose 180gr.
 
If there is no gas check, where would the over pressurization transmit to going aft? Through the firing pin hole, then along the axis of the bolt internally, and then out of the cocking piece? Is it possible that I did feel that on the shots that it broke through?
 
There are no pressure release/blow ofd valves in any firearm IM aware of....well besides atmospheric venting on some semi auto systems.....and maybe barrel porting/brakes, depending....

Some bolt actions have a gas release port in case there is primer rupture or a case head separation to prevent the gases winding up in the shooters face or the receiver blowing up. That was an improvement on different model early Mausers. I think the final improvement was on the M98's.
 
351 Winchester has the right of it I think given lack of previous problems. The end of the firing pin should be in a ball shape but the tips are hardened so they can chip (which is why some folks get bent out of shape with someone dry firing their rifles). The problem worsens after the first pierced primer usually. FWIW, the Enfield design, both the No. 1, No. 4, and No. 5 rifles have a gas release hole in the left side of the receiver wall in case of gas events inside the receiver like a pierced primer. The rimmed case head normally reduces the problems compared with rimless cases involving case separations.

You can change the firing pin protrusion but the only reason to do that is to fit a new firing pin. The firing pin is threaded into the cocking piece and has a retaining screw that locks it into place. If the rifle was working without piercing primers and then started up suddenly, chances are that the firing pin is damaged in some way. Easier and cheaper just to fit a replacement firing pins are available but you will need a special tool to remove the firing pin which is pretty cheap. http://e-sarcoinc.com/images/products/detail/le3067.jpg

Here is another way to do it, https://www.gunandgame.com/threads/removing-enfield-firing-pin-without-breaking-the-tool.101048/

Here is Apex with a firing pin for $16.95 and other places have them including new old stock. https://www.apexgunparts.com/enfield-4-firing-pin-used-good-pending.html
 
It's my understanding that the primer actually stops firing pin travel when a round is fired, so firing pin protrusion should not be an issue? I could be wrong there tho.
Some bolt actions have a gas release port in case there is primer rupture or a case head separation to prevent the gases winding up in the shooters face or the receiver blowing up. That was an improvement on different model early Mausers. I think the final improvement was on the M98's.
Those arnt really what I ment by gas relief valves, they are simply a way to vent pressure, debris, and hot gasses away from the shooter should there be a failure in the containment system....Tho It IS kinda hard to argue that they dont serve the same purpose just in a less controlled way.
 
If there is no gas check, where would the over pressurization transmit to going aft? Through the firing pin hole, then along the axis of the bolt internally, and then out of the cocking piece? Is it possible that I did feel that on the shots that it broke through?
yeah, youll usually feel some blowby on a pierced primer, even with guns that are vented. My 700 in 6x47 would punch primers if federal SMRP or other softer primers were used. Every time it happend youd get a puff of crap in the face out the back of the action.
 
It's my understanding that the primer actually stops firing pin travel when a round is fired, so firing pin protrusion should not be an issue? I could be wrong there tho.
Eventually, the material ahead of the firing pin will stop further forward motion of the firing pin.... Some .32 ACP pistols use the firing pin as the ejector and have a maximum FP protrusion of about 3/16 inch.

However - the firing pin should only protrude enough to compress the cup against the anvil, any further it can weaken the cup and cause a pierced primer with a high pressure cartridge.
 
The bolt head on the Enfield unscrews so the head can be changed to adjust headspacing. Your bolt head should have a number on it. If my memory is correct I believe there were 5 different thicknesses made, although that would likely not be the cause of the pierced primers if it never did it before. Also, most of my WWI and WWII era rifles have a vent port either on the side or top.
 
It's my understanding that the primer actually stops firing pin travel when a round is fired, so firing pin protrusion should not be an issue? I could be wrong there.....

You are. There is a step-down on the firing pin which hits the end of the interior of the bolt and stops firing pin travel. Otherwise if the trigger was pulled on an empty chamber the pin would fly out of the bolt and down the barrel.

An excessive firing pin protrusion certainly can cause pierced primers, but if this only happens occasionally then the cause is likely elsewhere, like pin tip condition.

upload_2019-12-27_7-9-40.jpeg
 
351 Winchester has the right of it I think given lack of previous problems. The end of the firing pin should be in a ball shape but the tips are hardened so they can chip (which is why some folks get bent out of shape with someone dry firing their rifles). The problem worsens after the first pierced primer usually. FWIW, the Enfield design, both the No. 1, No. 4, and No. 5 rifles have a gas release hole in the left side of the receiver wall in case of gas events inside the receiver like a pierced primer. The rimmed case head normally reduces the problems compared with rimless cases involving case separations.

You can change the firing pin protrusion but the only reason to do that is to fit a new firing pin. The firing pin is threaded into the cocking piece and has a retaining screw that locks it into place. If the rifle was working without piercing primers and then started up suddenly, chances are that the firing pin is damaged in some way. Easier and cheaper just to fit a replacement firing pins are available but you will need a special tool to remove the firing pin which is pretty cheap. http://e-sarcoinc.com/images/products/detail/le3067.jpg

Here is another way to do it, https://www.gunandgame.com/threads/removing-enfield-firing-pin-without-breaking-the-tool.101048/

Here is Apex with a firing pin for $16.95 and other places have them including new old stock. https://www.apexgunparts.com/enfield-4-firing-pin-used-good-pending.html

Awesome info. Thanks!
 
The bolt head on the Enfield unscrews so the head can be changed to adjust headspacing. Your bolt head should have a number on it. If my memory is correct I believe there were 5 different thicknesses made, although that would likely not be the cause of the pierced primers if it never did it before. Also, most of my WWI and WWII era rifles have a vent port either on the side or top.

Good stuff. Thanks!
 
I worked a long day yesterday and went home, ate and then crashed so I didn't look at it but I will and I'll for sure report on the several possibilities that you folks have suggested. It is appreciated.
 
You are. There is a step-down on the firing pin which hits the end of the interior of the bolt and stops firing pin travel. Otherwise if the trigger was pulled on an empty chamber the pin would fly out of the bolt and down the barrel.

Eventually, the material ahead of the firing pin will stop further forward motion of the firing pin.... Some .32 ACP pistols use the firing pin as the ejector and have a maximum FP protrusion of about 3/16 inch.

However - the firing pin should only protrude enough to compress the cup against the anvil, any further it can weaken the cup and cause a pierced primer with a high pressure cartridge.
Thanks guys, my understanding of how a the firing pin interacts with the primer is mostly from reading.
Ive had one rifle that pierced all but the toughest srps regularly and examining firing pin protrusion was what started me on looking into what happens when a round is under the hammer.
 
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