Chambering the same round in your AR

[Excalibur]

I actually rotate my HD gun, which is an AR every 6 months of the ammo inside it. It's always chambered and the only time it is unloaded, is either for cleaning after the range or transporting somewhere. A reminder came to me when I was practicing is to not chamber the same round over and over again because the firing pin on an AR is floating and it indents the back every time and might lead to a problem.

What does everyone know about this really? I do know the firing pin does lightly indent the back when you chamber a round, but I've never actually heard about it slam firing the gun or messing up the round.

 

[throttletony]

hmm, good question.
As to the primer and a floating firing pin, you could let the bolt close smoothly (charging handle pulled all the way back and follow it forward slowly, forward assist to close if it doesn't fully go into battery)
I don't know if it's worth worrying about too much. The firing pin needs to hit the primer quite hard -- not sure if you could get cumulative effects to equal the force needed.
Also, remember bullet setback from chambering. It can happen in rifles, though it's much more prevalent in pistols. Again, I wouldn't worry too much about it. It's a good idea to rotate through ammo anyways, especially if it's been chambered a bunch of different times (rifle rounds have greater neck tension than most pistol rounds, so the effect wouldn't be as obvious as soon)
If the AR sits undisturbed for 6 months, it's not a problem. But, if you go shooting every week, and rechamber your SD rounds afterwards, it could have an effect. Personally, I'd feel comfortable rechambering a .223 5-10 times, maybe a bit more. But, if possible I wouldn't want to shoot the round that's been chambered and ejected 50 times.

Anyone feel free to correct me if I'm wrong on this stuff.

 

[joe138]

As I understand it, the firing pin repeatedly touching the primer while chambering can result in a dead primer. Or a primer that is so dented that the firing pin will not srike it properly. I rotate duty ammo in my ar often to avoid these possibilities.

 

[bwframe]

As I understand it, the firing pin repeatedly touching the primer while chambering can result in a dead primer. Or a primer that is so dented that the firing pin will not srike it properly. I rotate duty ammo in my ar often to avoid these possibilities.

 

[natdscott]

The pin will 100% fo sho light a primer every now and then. Not as bad as the M1A, but do NOT trust it.

Frankly, it's better to hand feed the first round and ease the bolt home and into full battery. Just drop it the last ~1/2" or so, and test with the FA for full battery.

This action eliminates the pin issue.

And no, I have NEVER heard of a verified example of a dead primer that could actually be attributed to repeated chambering.

...but I still wouldn't do it. He who dies first made the most mistakes.

-Nate

 

[BehindBlueI's]

It can kill the primer. How many times it takes varies, but there is professional testing that deals with it. I don't know if it's open source or not. The resulting recommendation was to use a previously chambered round for training only. Probably overkill, but stakes are high, cost is low.

 

[Trigger Time]

For those worried about it just don't chamber your long gun. I'd never tell,someone to do that with a pistol and i personaly keep mine chambered. Also I rotate the first round in the mags of my pistols and rifles if I have to unchamber the round

 

[CMB69]

What does everyone know about this really? I do know the firing pin does lightly indent the back when you chamber a round, but I've never actually heard about it slam firing the gun or messing up the round.

That is the definition of slam fire. Happened to me once in the Army, and have seen it a couple of more times at High Power matches. Fortunately, it does not occur often.

When teaching people new to AR's, I always show them the dented primer and make sure they know / understand that slam fire can happen.

 

[dudley0]

It can kill the primer. How many times it takes varies, but there is professional testing that deals with it. I don't know if it's open source or not. The resulting recommendation was to use a previously chambered round for training only. Probably overkill, but stakes are high, cost is low.

DocGKR has posted his findings. He also mentions a pretty good sized SWAT unit that had a no go on an entry rifle. They took the rifle and the round and tested only to find that the primer had been pushed in just enough that it wouldn't ignite.

I talked to him about it at one time, trying to get a closer number on the amount of times before problems. He was very adamant about never re-chambering an SD round. When I mentioned cost I was reminded that it was cheaper than a life. I was also in a discussion where the realization came that I do not take that rifle out every day for practice, so eating a costly round once in a while would not be that bad.

I like the idea of easing the bolt and using the FA to make sure it is seated.