300BlkTalk

Are the Federal and Winchester primer cups hard enough to prevent slam fire in an AR or do I need to stick with CCI and Remington?

I have used Winchester small rifle primers in an AR for 15 years and never had a problem.

Never had a slam fire.

I use whatever is cheapest. Fiocchi SR mag was my last bulk buy. They work fine.

I use what I have....from Russian to Serbian to American, in 40 plus years of loading and shooting a crap ton of .223, I never had a slam fire, either.

I use the WW Small Rifle and the CCI #41. They are both excellent primers with harder cups than the average, especially the #41's. An AR will slam fire just like an M1 or an M1A, I have seen it, so using primers with a known reputation for better resistance to the event is just good sense.

Here is a link to a good thread on primer thickness. It's not my post nor can I vouch for the correctness of the information. I use it as a point of reference.

https://www.shootersforum.com/handloadi ... ers-2.html Look for post #24

I have on the shelf....Tula, Sellier Billiot, Remington, Winchester, CCI and Federal primers both regular and magnum. I would not hesitate to use ANY of them in my AR's.

Part of the problem with slam fires is the one doing the loading.....if you don't seat your primers properly (leave them high) you increase your risk of having a slam fire or a failure to fire (as the firing pin can push the primer forward, instead of crushing). There are some mechanical problems with some rifles that also increase the chance of a slam fire. Broken firing pin can cause a slam fire or a failure to fire, for instance.

Again, in MY experiences I have not had a problem. One of my practices is that I don't slam the bolt forward on a cartridge repeatedly. As we all know, inertia causes the firing pin on a AR to slide forward each time contacting the primer. I don't temp fate

In my experience, Federal seems to have the softest cups. When I put Micalek hammer springs in my revolvers for a 6# double action pull, federals were the only primers that the hammer strike would detonate. The firing pins would barely dent the Winchesters. Those two brands were the only ones we used. I've got around 50K Wolf pistol primers that seem to be very hard plus about 5K of AR.

Some what related to slam fires...

Do not use small rifle primers that are too soft for the pressure of the cartridge or you might get pierced primers with the gas eroding the bolt face and firing pin.

For example, at full power .223/Blackout pressures it is possible for pierced primers with Remington 6 1/2 and Wolf/Tula "regular" (KVB223) (not the 5.56 or .223 Remington marked boxes) small rifle primers. I guarantee it's happened to me. I now use the remainder of those primers for 30 carbine and low pressure subsonic Blackout loads with 108gr M160 frangible bullets.

rlandry6 wrote:In my experience, Federal seems to have the softest cups. When I put Micalek hprimersammer springs in y revolvers for a 5# double action pull, federals were the only primers that the hammer strike would detonate. The firing pins would barely dent the Winchesters. Those two brands were the only ones we used. I've got around 50K Wolf pistol primers that seem to be very hard plus about 5L of AR.

Federal makes a dedicated AR match primer.

Powder Vally sells them, but they show to be out of stock.