5.56 reloading, which primers for AR-15?

[Pinecone]

So how do you distinguish between a slam-fire and/or a bump fire?

Slam fire comes from the bolt closing. It can occur when you just drop the bolt. You can have the hammer follow or the sear trip when dropping the bolt, but you can see that happen without a round.

Bump fire is due to trigger activation due to the rifle moving and the finger not. See how a bump fire stock works.

 

[Pinecone]

Everything I've ever read indicates that it's the floating pin combined with a high primer that's required to induce a slamfire in an AR15.

It seems also soft primer cups can cause issues.

The CCI #41 is specifically designed to prevent this, and what is loaded into military ammunition.

Harder and thicker cup, and more space between the cup and the anvil.

 

[Speed3]

It seems also soft primer cups can cause issues.

The CCI #41 is specifically designed to prevent this, and what is loaded into military ammunition.

Harder and thicker cup, and more space between the cup and the anvil.

I still have not had a slam fire with thousands of CCI BR primers...I've only heard of the mythical slam fire on the internet lol

 

[BigRick]

You guys call it a slam fire, I call it a "double tap" still I've never seen it.

 

[outrider58]

Slam fire comes from the bolt closing. It can occur when you just drop the bolt. You can have the hammer follow or the sear trip when dropping the bolt, but you can see that happen without a round.

Bump fire is due to trigger activation due to the rifle moving and the finger not. See how a bump fire stock works.

I didn't ask "what's the difference". I know what the difference is. My point was, you really don't know whether you just experienced a slam fire or a bump fire(I prefer 'double tap') when it happens during a shot sequence.

 

[atblis]

There are plenty of good write ups about slam fires. One particular experimenter was only able to induce one when a high primer was combined with excessive firing pin protrusion. At that, I believe it usually took a couple bolt drops on the same round to ignite the primer.

I suppose when dealing with a contact explosive, lead styphnate in this case, there's always the possibility it explodes with the smallest of shocks.

 

[Jaybeez]

Everything I've ever read indicates that it's the floating pin combined with a high primer that's required to induce a slamfire in an AR15.

I forget the name of the case, but it involved an early gen olympic arms AR, and an atf tech branch that loaded soft primer ammo to induce slam fires and full auto.

 

[Jaybeez]

I still have not had a slam fire with thousands of CCI BR primers...I've only heard of the mythical slam fire on the internet lol

CCI BR primers have harder cups. As do magnums. Think about it, most BR calibers are screaming hot and loaded to max pressures.

 

[Uncle Duke]

A good read IMO on many of the thoughts mentioned in this thread.

41's for me in the AR. As mentioned, a thicker cup and additional spacing to the anvil. Not that many or most are inclined to look, or think of looking or typically need to look. But it's a bit unnerving to me to see a dimpled primer on an unfired cartridge consistent with the floating firing pin inherent to the AR. At a buck a hundred price difference and usually less, cheap insurance to go mil spec in my view.

http://ingunowners.com/forums/ammunition-reloading/174704-choosing-right-primer.html

 

[DaemonAssassin]

If your primer is seated to the proper depth, you won't have slam fires. If your firing pin is still within spec, you won't have a slam fire. Simple take aways from this are, make sure the primer is seated properly and properly maintain your rifle.

 

[outrider58]

If your primer is seated to the proper depth, you won't have slam fires. If your firing pin is still within spec, you won't have a slam fire. Simple take aways from this are, make sure the primer is seated properly and properly maintain your rifle.

Bingo!

 

[Pinecone]

I didn't ask "what's the difference". I know what the difference is. My point was, you really don't know whether you just experienced a slam fire or a bump fire(I prefer 'double tap') when it happens during a shot sequence.

True.

Even if you just drop the bolt and it fires, it could be the sear tripping.