CCI #34 Mil Spec Large Rifle Primers for 7.62x39?

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  • Last Post 06 February 2010
kokojoe posted this 22 September 2009

I recently started loading the 7.62 x 39 with my own cast bullets.  This has been successful based mostly on C.E. Harris' work.

I've used the Federal Match Large Rifle primers because that is what was available. 

I shoot from a Chinese SKS.

As I've been looking into the tight S&B primer pockets, I've read many posts about slam fires with the SKS and regular primers.  These posts seem to indicate that for auto loader military rifles the #34 CCI should be used because it takes a harder strike to ignite.

I've not yet read up on the particulars of the firing pin - but this seems to be due to the design of the military pins.  And, further, some of the comments seemt to indicate that it becomes more of an issue as the firearm components wear.  There seems to be some type of tool and/or measurement that can be done to determine the condition of the firing pin in these actions.

I've put through a few hundred rounds without incident.  I just wondered what opinions and experiences were with this - specifically with the Chinese SKS?  I do recall reading that these primers were definately recommended for the Garand.

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JetMech posted this 22 September 2009

It's a floating firing pin design, same as the Garand. As the bolt moves forward, in imparts forward momentum to the firing pin. When the bolt stops it's forward movement by engaging the locking lugs and breech face, the pin still has forward momentum, causing it to strike the primer. Normally not enough to fire the round. Interestingly, it was not a part of the original Kalisnikov design, but was changed later. That's why #34s are recommended.

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Ed Harris posted this 23 September 2009

If a Garand is properly set up the firing pin doesn't “float.” It is mechanically retracted by a on the receiver web, which engages the “tail” of the firing pin. This is also true of the M14, Ruger Mini-14 and Mini-Thirty. Gaging firing pin retraction is a 100% check, and failures are a critical defect. The firing pin tip must be flush or below the boltface at “half-lock,” about 7-1/2 degrees of bolt opening.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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JetMech posted this 23 September 2009

Thank you, sir, for the correction. As always, your knowledge, as well as your willingness to assist us less educated is invaluable.

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kokojoe posted this 24 September 2009

After reading more about this, slam firing seems like a really bad thing to have happen!  With any primers hard enough to find, I could make no headway whatsoever on finding any CCI #34.

But, while searching, I stumbled on an interesting link:

http://www.murraysguns.com/sksown.htm

This is a gunsmith-made spring operated firing pin for the SKS.  I sent my bolt off to him today.  For $47 (including shipping back) installed, sounds like a safe and conservative approach for someone like myself who will use almost exclusively hand loads and can stick with standard primers.  Also, I have kids & others who shoot this gun.

Thanks for all the input.  Let me know if anyone has experience with this modification.

I'll post and update when I get it back & use it.

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mlr1m posted this 04 February 2010

Personally I only use federal primers in firearms that do not have a floating firing pin. I have used cci-34 whenever I reload for my m-1a.

I have been told that if the milspec primers are not available that I should use anything but federal. I have been wondering about the cup hardness of wolf primers as the cci's are not available to me right now.

Michael

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JSH posted this 04 February 2010

I all but wore an SKS out in the 12-15 years I had it. It ran with a huge variety of ammo, handloads, surplus and commercial. I wouldn't even want to guess how many rounds were fired through that thing. Never once was there a slam fire. I have to put a plug in for the SKS's. A veteran friend of mine fooled with it and turned it into a good shooter. I think some of the slam fire issues I have heard of may be from some “bubba's trying to improve on the trigger and not knowing what they are doing. In a way I wish I had that old rifle back. There is no way I could afford to feed it, if i shot it the way I did back then. Ammo could be had for cheap, cheaper than 22 mags at the time. jeff

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Ed Harris posted this 04 February 2010

On the SKS the driven firing pin protrusion is much more than necessary for US primers. If you adjust driven protrusion within the range of 0.028-0.032” you should be OK with standard US Large Rifle primers. Do not reduce the striker point diameter, but if the tip is sharp it is OK to reshape it to a smooth hemisphere.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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rockquarry posted this 04 February 2010

I purchased two new Norinco SKSs about fifteen years ago. One would regularly slam- fire, but only with CCI-primed handloads; did fine with the cheap surplus ammo. CCI 34 primers are supposedly harder to lessen or prevent the slam-fire problem. Someone mentioned the “Murray kit". I had these installed on both my guns. Cheap insurance and they apparently work. In defense of the SKS, the gun will shoot cast bullets at least as accurately as jacketed.

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giorgio de galleani posted this 04 February 2010

My Norinco SKS has a wide flat point firing pin,I'll round a bit the circumference .

I am using  up a small quantity of white box CCI primers. 

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RockChuck posted this 06 February 2010

Gentlemen/Ladies,

Does the potential exist for this type of slam fire with the AK47 and clones?  Does  reloading cast for these firearms require any further cautions in the normal reloading procedures other  than to full length resize?  Thank you for your time and consideration.

Chuck Martin

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NuJudge posted this 06 February 2010

I have seen doubling in Kalashnikov rifles using really soft PMC/Murom Berdan primers.

There is a retrofit kit available commercially to put a firing pin retraction spring in the SKS: http://www.murraysguns.com/sksown.htm>http://www.murraysguns.com/sksown.htm

There are various systems of converting Kalashnikov bolts to have a firing pin retraction spring. Some links: http://www.k-var.com/shop/product.php?productid=16548&cat=279&page=1>http://www.k-var.com/shop/product.php?productid=16548&cat=279&page=1 http://www.akfiles.coms/showthread.php?t=34571&highlight=spring+loaded+firing+pin>http://www.akfiles.coms/showthread.php?t=34571&highlight=spring+loaded+firing+pin http://pookieweb.net/AKM/AK_308/bolt_308.htm>http://pookieweb.net/AKM/AK308/bolt308.htm

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