Author Topic: Popped Primer Problem (update 6-28-13 Found a CURE)  (Read 67578 times)

0 Members and 1 Guest are viewing this topic.

murray

  • Life Member
  • SKS Gunsmith
  • *****
  • Posts: 2052
    • https://murraysguns.com
Popped Primer Problem (update 6-28-13 Found a CURE)
« on: April 28, 2008, 11:10:41 AM »
Some may call it "Pierced Primers" but whatever you call it, it's a problem for many SKS owners trying to use "that" ammo. While this may not cure 100% of the problem with all rifles, it seems to be having some very positive results. And you can learn about "it" by clicking on the link at the bottom of this post, then click on the link at the top left of that page. It's currently a PDF doc but should be changed to just another page at murraysguns.com in the near future.

The "before" pics you'll see there are a good indication why you should not dry-fire the SKS with an original firing pin, and how doing so, (or the previous owner did?) is contributing to the "popped primer" issues.

All feedback is welcome!
« Last Edit: June 28, 2013, 03:10:37 PM by murray »
https://murraysguns.com/shop/

If you feed it junk ammo, why should you expect filet mignon results? Well now you can, with our new "Neck & Throat" chamber reaming service!

Kivaari

  • SKS Sniper
  • *****
  • Posts: 526
    • Kivaari's Little Armory
Re: Popped Primer Problem
« Reply #1 on: May 17, 2008, 12:34:41 AM »
It would seem that dry firing is "peining" the stop from the inside causing the "volcano"...

If the primers are so hard, how is the raised edge "cookie cutting" the primer?? Have you done this without the pin or are there serrations, like a cannelure on the surface of the primer?

Previous rifles, Mosins in particular, I've corrected this by keeping the same protrusion yet sharpening/reshaping the tip. In my case, a large, flat firing pin tip caused the issue. Did you not recently change tip shapes or am I on another planet?

"That" ammo is a pain in the arse.
kivaari
quality and correctly engaging SKS trigger tune

SKS....the militia's rifle!

www.kivaari.com

NRA Life Member
Texas State Rifle Association member

murray

  • Life Member
  • SKS Gunsmith
  • *****
  • Posts: 2052
    • https://murraysguns.com
Re: Popped Primer Problem
« Reply #2 on: May 17, 2008, 10:49:15 AM »
To tell you the truth, I'd like to know who came up with the terms "hard" and "soft" primers. I'm beginning to believe the terms were applied simply because the foreign supplied Berdan primers have been less than good quality for many years. Is it possible they are just defective and don't ignite consistently or is the material the primers are made of really "harder" than that Boxer primers are made of? Or, are the Berdan primers just a little more brittle, thus the tendency to fail to ignite and shear into the firing pin hole?
All I know is, the empty cartridge will have a primer with a neat round hole in it, and the round piece that seperates will either be inside bolt, sticking in the firing pin hole, stuck to the tip of the firing pin, or loose elsewhere in the receiver.
None of the pieces that we've examined were actually "pierced" by the firing pin tip, they were simply "blown" out and into or through firing pin hole.
And when we changed the design of our FP tip, we again followed the example of the original Russian designed firing pin tip. Our theory is that the primer might be getting "cookie cut" due to a larger than normal amount of surface area that is unsupported at ignition. With an original or sharper tipped FP, there is a substantial amount of unsupported primer between outside diameter of FP and inside diameter of FP hole. With the larger radiused tip, (like the original Russians) you get almost complete support.

And yes, I definitely have seen rounds that were properly loaded into chamber, not fired but carefully extracted, and there would be a visible "ring" mark on the primer created by the FPs "volcano."

As much as I dislike "that" ammo, I dislike the foreign suppliers that export it to us even more!!! Why does that company export steel cased, Berdan primed ammo to America, but won't export any of their brass cased Boxer primed ammo, in 7.62x39? Keeping the good stuff and sending us the trash?   :x

We've considered the idea of creating a FP tip that had a small .050 to .060 tip for the first .030, then increasing to the .090 diameter, so that a smaller tip actually ignites the primer, but the larger area helps support the primer surface. But we haven't had a chance to extensively test this design as we also want to include testing of bolt that has had a bushing installed that simply reduced FP hole size from .090 to the more normal .060. That may prove to be a better cure than anything else.

I'd prefer that "they" just let loose with some of the good stuff.   ;)

https://murraysguns.com/shop/

If you feed it junk ammo, why should you expect filet mignon results? Well now you can, with our new "Neck & Throat" chamber reaming service!

Kivaari

  • SKS Sniper
  • *****
  • Posts: 526
    • Kivaari's Little Armory
Re: Popped Primer Problem
« Reply #3 on: May 17, 2008, 11:40:42 AM »
Well hard and soft came from military/commercial. Inertia pin rifles needed the harder primer to take a small amount of firing pin tip momentum...and I know you know this. :^)

The recent Wolff production is much different , in my memory, than previous production....say 5-7 years ago. My personal theory is that the better ammo is in Iraq and elsewhere on the front lines.... The rest is ours.. This explains the "new and improved" Military Classic moniker.

People need to quit buying this crap...imho....
kivaari
quality and correctly engaging SKS trigger tune

SKS....the militia's rifle!

www.kivaari.com

NRA Life Member
Texas State Rifle Association member

murray

  • Life Member
  • SKS Gunsmith
  • *****
  • Posts: 2052
    • https://murraysguns.com
Re: Popped Primer Problem
« Reply #4 on: May 17, 2008, 11:51:39 AM »
Quote
People need to quit buying this crap...imho....

Ditto!!!!

I understand the "hard/military" and "soft/commercial" aspect, I'm just not sure if the material the military primers are made of is harder on the Rockwell scale, or do the military primers just take a harder strike from the FP to ignite dependably? Or both?

https://murraysguns.com/shop/

If you feed it junk ammo, why should you expect filet mignon results? Well now you can, with our new "Neck & Throat" chamber reaming service!

fistful of steel

  • SKS Shooter
  • **
  • Posts: 93
Re: Popped Primer Problem
« Reply #5 on: August 18, 2009, 08:23:01 AM »
How about a recommendation on where/what ammo to buy?  I like Ammonman for the no BS price to the door for a case of ammo.
Know your rights.  The future is unwritten.

Huff

  • Board Supporter
  • SKS Marksman
  • *****
  • Posts: 193
Re: Popped Primer Problem
« Reply #6 on: July 16, 2012, 02:01:10 AM »
I recently won the raffle and was very impressed with the work of art being the Murrays firing pin. But I now have experienced "popped, pierced primers".  Looking at the new pin I cannot see why it would cause this problem but I haave gone back to my original firing pin. I cannot see any obvious volcanoing around the hole but I can see what looks like a little ring on the primers that arent pierced. I will test the rifle tomorrow with the same ammo and see what happens. I have been using this ammo all along with no problem before in my MAK90 and this SKS. My SKS is fairly new, it was unissued, unfired and is in great shape.
huff
Gun Totin' Liberal Navy Vet (not a "Liberal") but civil libertarian.

Trasi

  • Board Supporter
  • SKS Newbie
  • *****
  • Posts: 11
Re: Popped Primer Problem
« Reply #7 on: July 16, 2012, 06:52:34 PM »
Let us know how it goes with the Original FP. Is it a Yugo?
Trasi
Murray's Guns

Huff

  • Board Supporter
  • SKS Marksman
  • *****
  • Posts: 193
Re: Popped Primer Problem
« Reply #8 on: July 27, 2012, 09:36:55 PM »
I have some pics and info in the thread "replacement firing pin" authored by Madmitch that has more good info and a resolution to the problem with my rifle. All worked out well!
huff
Gun Totin' Liberal Navy Vet (not a "Liberal") but civil libertarian.

Huff

  • Board Supporter
  • SKS Marksman
  • *****
  • Posts: 193
Re: Popped Primer Problem
« Reply #9 on: August 10, 2012, 12:21:59 AM »
One final statement. I am using the Murray firing pin and am happy. After champhering the firing pin hole with a needle file and smoothing the bolt face, everything looks good. It is a Yugo and the Yugo's do have a very square and sharp edge in the FP hole and the " popped primers" on my gun looked like they were cut with a cookie cutter.
I will use current production ammo from now on also.
thanks Murray for all the help and patience, keep up the good work.
huff
Gun Totin' Liberal Navy Vet (not a "Liberal") but civil libertarian.

murray

  • Life Member
  • SKS Gunsmith
  • *****
  • Posts: 2052
    • https://murraysguns.com
Re: Popped Primer Problem
« Reply #10 on: August 10, 2012, 03:22:48 PM »
Whoa, I know some things are bigger here, but...

Wecome aboard gijack!

We do lay claim to stopping slam fires, but compromised primers are something else entirely. We are supplying them with slightly less protrusion to reduce the possibility of popped primers, but no guarantee. That's an ammo issue, unfortunately.

https://murraysguns.com/shop/

If you feed it junk ammo, why should you expect filet mignon results? Well now you can, with our new "Neck & Throat" chamber reaming service!

sks2012

  • SKS Marksman
  • ***
  • Posts: 106
Re: Popped Primer Problem
« Reply #11 on: January 06, 2013, 02:49:12 PM »
I have the Murrays firing pin and I'm popin primers on wolf. I'm going to gently smooth the firing pin(bolt face) and give it a turn by hand with a 82 degree reamer.

FJRrider

  • SKS Marksman
  • ***
  • Posts: 103
Re: Popped Primer Problem
« Reply #12 on: February 13, 2013, 06:19:04 PM »
Shot my Chinese SKS for the first time on Sunday and experienced about a 20% non fire rate. All the rounds that didn't fire looked like they had a light strike on the primer. By the end of the session (about 50 rounds cycled) the gun stopped shootig at all. I looked at the front of the bolt and could see something shiny in the firing pin hole. "popped primer" I thought.

I finally got a chance to tear the gun down today and the Murray's firing pin wasn't moving at all. I could also see what appeared to be that raised edge around the hole.

I removed the pin retainer but the firing pin still wouldn't budge. I finally got it to move by grasping the rear of it with channel locks (I know but I was careful).

When I banged the bolt on a folded rag laying on the table 3 little metal pieces came out. But no spring. The firing pin still won't go in and out smoothly and I can't seem to get the spring, which I know has to be in there, to come out either.

Any thoughts or suggestions? I'm guessing something is still jammed in there although I can't see anything.

Oh and I was shooting Wolf Polyformance FMJ.

Help please!  :cry:


FJRrider

  • SKS Marksman
  • ***
  • Posts: 103
Re: Popped Primer Problem
« Reply #13 on: February 13, 2013, 06:34:59 PM »
Well I finally got the spring to come out and another piece of primer came with it. The spring is, umm, not quite in its original condition anymore though.

Looks like I'm going to have to smooth out the firing pin hole on the bolt face before shooting again. Luckily I bought some spare springs from Murray!

The spring on the left is the one that I just extracted from the bolt and the spring on the right is what it should look like.


murray

  • Life Member
  • SKS Gunsmith
  • *****
  • Posts: 2052
    • https://murraysguns.com
Re: Popped Primer Problem
« Reply #14 on: February 13, 2013, 06:51:29 PM »
Yep, the hot gases blowing back through the bolt would fry any spring made from any material. But there is something new on the horizon that could be better than the bolt face treatment, at stopping them from happenning.  8)
https://murraysguns.com/shop/

If you feed it junk ammo, why should you expect filet mignon results? Well now you can, with our new "Neck & Throat" chamber reaming service!