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jaybic
03-26-2009, 04:51 PM
Hey guys,

As if the primer thing hasnt been beat up enough, I have a question.

I have heard not to use certain brands of primers in an AR due to soft cups and the risk of a slam-fire but I dont remember which ones. I normally use CCI BRs for it and I know that they're ok but in the days of "buy what you can find", I want to know what NOT to use. Been shot once. Aint no fun and dont want to do it again.

Any ideas which those are?

Thanks,

Jamie

Larry Elliott
03-26-2009, 05:10 PM
I've been using WSR's and haven't had any slamfires. With a Tubb carrier weight system and a Tubb flat wire buffer spring using ~23.5 gr RL-15/75 gr Hornady HPBT's, and 55 gr FMJBT's/25 gr Benchmark with no carrier weight and the standard buffer spring.

A heavier/harder primer cup might help, but the WSR's which aren't particularly hard seem to work fine for me.

J. Pendergraft
03-26-2009, 06:08 PM
I have used several brands and never a problem. The firing pin will just barely mark the primer from the inertia of the bolt closing. IMO if there is a slam fire then likely there is some sort of mechanical malfunction.

Paul Fielder
03-26-2009, 06:21 PM
What do you guys think of the CCI small magnum primers?? These were the only ones available.

I too had been using RL15 and 75g hornady's.....was getting +/-2,825fps with the CCI br primer & good accuracy.

Any thoughts what this will cause in regards to grouping ??

thanks

Locoweed
03-27-2009, 08:06 AM
I've always heard that Federal makes the softest primers but look at all the military ammo using them.

HovisKM
03-27-2009, 09:23 AM
The best answer is to use....mil spec primers. CCI and Federal both make these. They have thicker cups. Also, I have heard the Wolf Mag's are quite thick also. The potential for a slam fire by the firing pin is there and is real. Might get away with firing hundred of thousands of rounds and not have a problem but it only takes once. There are many reasons for the thicker cup to include shipping and handling safety, stove piping on a live round, etc.

Hovis

Larry Elliott
03-27-2009, 11:26 AM
I've always heard that Federal makes the softest primers but look at all the military ammo using them.

The owners of Federal, ATK, operates Lake City ammunition plant, but the ammunition turned out there isn't the same as Federal commercial (FC headstamp) ammunition. A comparison of LC 5.56 cases and FC .223 Rem cases is a pretty clear demonstration of that. The LC cases are lighter, and have heads harder than the Hubs of Hades, while FC cases tend to be much softer.

Hovis is likely right, but if someone wants to shoot an AR, Garand, or other self-loading rifle it's either use factory ammunition or load with primers that are available. :(

jaybic
03-27-2009, 12:06 PM
How does a guy distinguish between the standard Federal or CCI(Br4s is what I have always used) and the Mil spec ones or are they one and the same?

HovisKM
03-27-2009, 02:26 PM
Jay,
They come in a different box and are marked as mil-spec or 5.56mm, etc. The BR-4 should actually work. They are a harder cup but not quite as hard as the mil-spec I believe.

Hovis

Winchester 69
03-27-2009, 03:25 PM
How does a guy distinguish between the standard Federal or CCI(Br4s is what I have always used) and the Mil spec ones or are they one and the same?
The MilSpec primers are available from CCI and cost app. 50% more than standard primers.
Small #41
Large #34
.

Gundog 64
03-27-2009, 03:57 PM
What primer to use in an AR. Use what you have. I shoot highpower and every brand of SR primer is someones top choice, I personally use BR4s. All this info floating around about dont use brand x primer as they have caused slamfires. Would someone who can acually prove that a slamfire IN AN AR was caused by using a certain brand of primer please prove it. I have been hearing this argument for years yet still have not met one person who has had a slamfire because of his primer cup being too soft. The story alwast ends up that they heard about it through someone else when you really push them to prove it.I have seen slamfires IN AN AR caused by faulty trigger work.
If anyone here has any primers they dont want to use in their AR send them to me I will gladly use them up in mine.

John Luitink
DR#1914

K Thomas
03-27-2009, 05:54 PM
Your biggest risk of slamfires in an AR come from an improperly seated primer, whatever the make. Yes there are special MilSpec primers available (the No. 41 has already been mentioned here), but the ARs aren't anywhere near as sensitive in this regard as were the M1/M14 family. Hard cups may be good, but proper seating of the primer, whatever primer, is the key here.

Incidentally, faulty trigger work won't cause a true slam fire. An AD, yes, but it's not a slam fire, per se. We're talking about discharge caused by the inertial firing pin delivering enough energy to detonate the primer, not a hammer following and firing a cartridge under a properly locked and "in battery" bolt.

Kevin Thomas
Berger Bullets

Gundog 64
03-27-2009, 06:29 PM
Your biggest risk of slamfires in an AR come from an improperly seated primer, whatever the make. Yes there are special MilSpec primers available (the No. 41 has already been mentioned here), but the ARs aren't anywhere near as sensitive in this regard as were the M1/M14 family. Hard cups may be good, but proper seating of the primer, whatever primer, is the key here.

Incidentally, faulty trigger work won't cause a true slam fire. An AD, yes, but it's not a slam fire, per se. We're talking about discharge caused by the inertial firing pin delivering enough energy to detonate the primer, not a hammer following and firing a cartridge under a properly locked and "in battery" bolt.

Kevin Thomas
Berger Bullets

Kevin,
Your post is spot on. You said it way better than I did.

John Luitink

zippy06
03-27-2009, 11:42 PM
Jaybic. Shoot what you can find.
Magnum. The thicker cups are for higher pressures.
Regular. They will work fine.
As long as they are seated properly. And the correct amount of powder is used. Long story, there.

BR4 primers have a very small "B" stamped on the outside of the cup.
Easy to see with a magnifying glass. Or +3.00 cheap sunglasses. For the guys, who don't want to be old.
I load for M1 and AR-15. Never a slam fire. :)
Plink and shoot matches at a local club.

It's a myth. It is usually something else. Prolly a dirty rifle/trigger asm.
Same guys complain about certain ammo. This and that. They don't bother me till the gun don't shoot. Ask "When was the last time, it was stripped and cleaned."? They get mad and walk away. :rolleyes:

Hi Kevin Thomas. +1.

Jaybic. Why did you get shot????
I got hit by 4 ricochets. Last year. But, I shoot bowling pins. :eek: