slam fire reloads

[genebofunk]

Well I had my first slam fire. I had loaded some rounds for my AR-15 and drove an hour to the range unpacked my stuff and realized that I had left my magazines at home. (****) But I wanted to try the loads out so I decided to hand load them into the chamber. I would load them in the chamber and the release the bolt with the catch and let it slam home. Suddenly after doing this painstakingly for an hour as I release the bolt and let it go home, bang. Ok, safe the rifle and make sure the muzzle was pointed in a safe direction, (actually the round hit the target). but I was quite embarrassed even though no one noticed. I check the rounds and the one that slam fired has a very distinctive mark on it compared the a normally fired round. The primer wasn't raised, is this something that is common when loading rounds in this manner?

 

[rcmodel]

Brand & model number of primer?

An AR-15 slam fire is not unheard of when dropping the bolt on a single loose round.
The thing is, an AR-15 floating firing pin hits every primer enough to leave a small ding in it when it chambers.

Feeding from the magazine slows the bolt carrier down somewhat due to the friction of pushing a round out of the mag and the FP impact isn't hard enough to fire it.

Yours with the extruded primer may have fired slightly out of battery when the bolt slammed shut, and then bounced back open slightly just as it went off.

Or, it was caused due to the fact the hammer was not fully down against the firing pin holding it against the primer flowing back into the hole in the bolt face.

I would check the inside of the case with a bent paper-clip and feel for a stretch ring anyway just in case it did fire slightly out of battery.

rc

 

[Ridgerunner665]

Options are...

Use mil-spec primers, CCI 41... http://www.midwayusa.com/Product/1301170074/cci-small-rifle-military-primers-41

A new firing pin...only if it keeps happening.

Yes...AR's sometimes do the slam fire thing, not very often though. Were those Federal primers by any chance?

 

[barnetmill]

I was taught when single loading the Garand to not release the bolt from the fully retracted position, but to let it go from about halfway back. This was meant to reduce the likelihood of slamfire. More likely to happen with commercial primes than military primers.

 

[genebofunk]

the primers were CCI 400 small rifle primers

 

[Ridgerunner665]

the primers were CCI 400 small rifle primers

Hmmm...thats a first for CCI primers (that I have heard of, but I haven't heard everything, LOL)

I have had one with Federal primers in an AR10...

 

[res45]

That's a classic slamfire primer,saw that with a CCI #400 loaded in a Remington X39 case fired in a SKS that doubled at the range. The CCI #400 primer has a thin cup .020" it's not recommended for using in AR style rifles,they didn't pass the bolt drop dimple test in my SKS rifles either.

According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably. I personally have never tested the theory and to my knowledge no other primer mfg. makes the same statement or claim about there primers.

Here is a pic of some bolt drop test I did on primer only cases with various primers in my SKS rifles with free floating firing pins. Regardless of primer used make sure it flush or seated below flush and always let the rd be stripped from the magazine.

L to R Lapua Berdan,Win. LR,CCI #34,CCI #400