Holes in my primers

[MGYSGT]

Ok, pretty sure I know the answer, but here goes. 30 BR @ 34.2 gr. of 4198. I use Rem brass for my 30 BR repeater and use it for Yotes. I think, the large hole in the primer pocket is the cause for holes in the primers. It doesn't do it when using the same load in my other 30 BR for benchrest. Same Barrel (Kreiger), same gunsmith (DD), same reciever, same chamber (.330), different brass (Lapua) with small primer holes. The only difference is the brass. It shoost very well, just pokes holes in the primer. This reciever was a 22-250 prior to a 30 BR. Do you think the firing pin difference between large and small primer is the culprit, or the size of the hole in the primer pocket? Do you think Mag primers will solve the problem? It pokes holes in the primers with CCI, Wolf, and Tula SR primers.

Tom

 

[jo191145]

Interesting.
Just to clarify. Your BR gun and yote gun share the same receiver/action/bolt/firing pin?
Maybe just me but thats how I'm reading your post.

I assume your using CCI-400 and Wolf nonmagnum primers.
Both are quite thin for any 30BR but I can't say they won't work. Never tried them in the 30BR.
I have some Magtech 7.5's that my guns pins will punch right through at any pressure level.
Any other primer is fine.

Did you see any signs of blanking/pinning on your way up to 43.2?

 

[markr]

The 30 BR develops PLENTY,000 of pressure to do funny things to non-specialized rifles. If it is a Rem 700...get the firing pin reduced in size (diameter) and the bolt bushed by Greg Tennel. Second. start using a primer with a strong cup, like a 9 1/2 Rem or other magnum primer, not that you need it to ignite the powder, but to provide a little more foundation to withstand the pressure. Third, reduce your load and work back up until you see signs of pressure again.
When you see "obvious signs" of pressure, please refer back to the reloading books that you have "read" and back things up until they go away!
In your instance you changed two major components of the four and you found some problems.
Mark

 

[Steve Wilson]

Not trying to be a wise guy here. Are you taking the firing pin assembly out of the bolt after popping the primers, to clean out the primer "disks" that wind up in there?

 

[MGYSGT]

Thanks for the input. Everything helps.

191145, new I would mess this up. Same brand of reciever (M700), not same reciever. Two diffent rifles. Just same brands of components. Yes you are correct in assuming the primers are standard and not mag primers. No there were no signs of overpressure building up the load. Started at 33 grs. and moved up until I reached 34.2 grs., which is the load I use in the other rifle.

Markr, I have considered mag primers and backing off of the charge a grain or so. While I understand that flat primers aren't the endall indication of overpressure. These primers are just not showing flat edges. They still have a slight roundness to the edges on them.

Steve Wilson, Taking the bolt apart and cleaning the inside out is first thing I did when I got it back home.

Perhaps I will send the bolt off, for some work on the firing pin. Mabey make it shorter, because I understand there is a difference in the length between one designed for use with large and small primers. Then have the firing pin hole sleeved.


Thanks
Tom

 

[gunsandgunsmithing]

This is almost always caused by the firing pin to bolt fit. Send it to GreTan. He'll have ya fixed and back to shooting in short order and very reasonably. Don't keep shooting it like this though. If you have a Jewell trigger in it, they fail because of this very problem. The leaking primer lets gas into the bolt and slams the firing pin rearward.--Mike

 

[243winxb]

Different brass- do both have the same size flash hole? Was the load worked up for each gun? Or 1 load fits all? Collection of reasons-

Pierced or Blanked Primers.

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1. Check the firing pin, it should have no gas cutting or deformities. 2. Firing pin protrusion should be checked. Internet search shows .055" to be about right for an AR15. Check with a gun smith as each firearm IS different. 3.The firing pin must stay in contact with the primer on firing. A weak hammer spring on an AR or a weak firing pin spring like on a Rem 700 bolt action will let the firing pin rebound on primer piercing when the hot gas pushes the pin backwards. 4.If the hole the pin sits in is to larger in diameter, the primer flowes back into this hole till the center of the primer separates and fall into the action or travels into the firing pin area. Bushing the firing pin hole will fix this. Or you may want to try a magnum primer with a thicker cup. Military ammo may have a crimp that needs to be removed before seating a new primer. The crimp is removed by reaming or swaging the primer pocket. Swaging may be needed here so the prime can be seated lower in the pocket. High primer = misfires & pierced primers. There is also a high pressure sign visible. The reloader was using a "starting" load and CCI 400 primers. The CCI 400 is thin & soft, change to a mag. or Rem. 7 1/2 primers. The pressure sign may have formed on firing the factory ammo. I just shot some XM193F factory, the web area expanded .0015" on firing. This is a sigh of a "hot" load.

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[markr]

Thanks for the input. Everything helps.

191145, new I would mess this up. Same brand of reciever (M700), not same reciever. Two diffent rifles. Just same brands of components. Yes you are correct in assuming the primers are standard and not mag primers. No there were no signs of overpressure building up the load. Started at 33 grs. and moved up until I reached 34.2 grs., which is the load I use in the other rifle.

Markr, I have considered mag primers and backing off of the charge a grain or so. While I understand that flat primers aren't the endall indication of overpressure. These primers are just not showing flat edges. They still have a slight roundness to the edges on them. Steve Wilson, Taking the bolt apart and cleaning the inside out is first thing I did when I got it back home.

Perhaps I will send the bolt off, for some work on the firing pin. Mabey make it shorter, because I understand there is a difference in the length between one designed for use with large and small primers. Then have the firing pin hole sleeved.


Thanks
Tom

If you start blanking primers, that should be indication enough that something is "not quite right" with the setup. Remington 700 actions are notorious for showing cratering of the primer, even with factory ammunition. Then when you add to that a higher intensity round than it came with (34.3 gr. of 4198 is not a full house load in a custom action), it will still display greater pressure than most if not all factory loads. Switching from Laqpua brass w/small rifle primer and small flash hole to Remington brass with a large rifle primer and large flash hole is reason enough to re-evaluate your load before you start shooting...those are reloading basics 101! Those basics say if you change one component that you should reduce the powder charge 10% or more in the case of much heavier bullets.
I'm not trying to be a wise a$$ here, I'm just trying to help people learn to keep themselves safe. Sixty thousand pounds per square inch of pressure two inches or less from your face and eyes can cause terrible things to happen. I just don't want you to be the one that it happens to.
Mark

 

[MGYSGT]

Thanks for the input everyone. Will pursue those options.

Tom