AR's, no chrome, jams, and slamfires

[Kamicosmos]

Today at the range, my Bushy Varminter experienced it's first jam.

RO calls cease fire just as I loaded a mag and closed the bolt. Could not get the bolt to open! I yanked and yanked, it wouldn't budge! Which reminded me that I need a tac handle to clear the scope, just for this type of situation!

Anyways, finally popped it out. My dad was with me, and after I got it cleared, he said: "I thought they fixed that after Vietnam? Mine always did that." I said they did with the advent of chrome lined barrels and chambers, but the Varminter doesn't have the chrome.

Now, that said, this was the gun's first jam, but I think the ammo was to blame. I think that particular round wasn't completely resized by me when I loaded it, since it 'jammed' with out firing first. And the brass was dirty, not polished like all the others, so I think it got missed in the resizing run.

Anyways, aside from keeping the gun spotless, and making sure the brass is sized properly, any tips on keeping a non chromed AR from jamming like that?

And, to make this post just a hair longer:
I'm trying to learn to not just hit the button and let the bolt slam shut. I'm trying to remember to hang onto the charge handle about half way, then let it slide shut and use the forward assist. I noticed when clearing my gun that primers showed a small ding from the firing pin on them.

Anything to do for that, other than change loading procedure? a special firing pin or something? The though of an accidental ND slam fire does not appeal to me very much!

 

[Sydwaiz]

I was taught to never ride the bolt carrier and to always let it fall completely on its own.

 

[Victor Romen]

Ding on the primer is okay. That is normal with a free floating firing pin. Likely hood of a slam fire is low even with commercial ammo, but is raised if you are single feeding with out a magazine. Of course loading with the gun pointed in a safe direction is always the best course of action.

 

[wanderinwalker]

Kamicosmos,

Let the bolt slam with the rifle pointed in a safe direction. It's how the thing was designed to work. Yes, single loading does increase the probability of slam-fire (in theory) but I have never had a problem on my rifle. Round into chamber, round half-way into chamber, round resting on magazine follower, no problems.

As to your jamming issues, sounds like you found your source already. Dirty and missized brass is the culprit. My AR has a stainless barrel and did exactly what you described a few times when it was new. Entirely due to my reloads. Haven't had a problem since I switched to an RCBS X-Die and adjusted it properly for my rifle.

And I know you have a scope on your rifle from your post, otherwise I suggest the following drill (taught to me by a Marine Corps Armorer):

1) Drop magazine and place safety ON.
2) Grasp charging handle in strong hand, grasp forearm with weak hand.
3) Point rifle vertical over hard, solid bench or table.
4) Briskly bring rifle butt onto hard surface, squarely, while yanking charging handle.

If you did this right, the action will clear relatively easily. And I'm sure it would work if you did the same manuever with the rifle pointed downrange, bringing the buttstock backwards into the front of something solid.

And as an addendum: You don't need to keep it spotless as long as the ammunition is sized properly.

 

[ID_shooting]

This is probably not the case, but worth asking.

Ever use any laqured ammo in it?

I have seen many ARs on the range with feed/extraction issues because as the chambr heats up, the coating comes off and goos the chamber, cleaning with a thinner then re-oiling the surface usually will clear this out.

 

[TechBrute]

If your scope won't stand up to a "stuck bolt drill" as described in a previous post, you need a new scope.

Let the bolt slam when you are loading.

The BM varmiter has a .223 match chamber, IIRC. It is more sensative to dirty and oversized ammo.

 

[Quintin Likely]

I'll echo the sentiment, don't ride the bolt home, hit the release and let it fly. The primer dimple is normal if you eject a chambered live round, since an AR has a floating firing pin. As long as your ammo's in spec, the chance of a slamfire in an AR is relatively non-existent compared to an M1 or M1A.

Just make sure your primers are seated at least .003" below the case head, if you're single loading it, make sure the round is pushed as far into the chamber as you can get it, and don't ride the bolt home, let it slam home with it's full force.

 

[Bartholomew Roberts]

The dimple is normal for free-floating firing pins like the AR15. A couple of things to help minimize the chance of a slamfire (besides those already mentioned in this thread).

1) Don't repeatedly chamber and re-chamber the same round. Repeated dimples on the primer make a slamfire more likely.

2) Keep the firing pin channel clean and clear of debris (pipe cleaner is good for this).

3) Check the Reloading forum for tips on primers. The military uses different primers than most commercial manufacturers, though you should be OK with either one.

Also, keep in mind the four rules and make sure the rifle is pointed in a safe direction when you release the bolt. Slamfires are exceedingly rare but they do happen.

 

[Kamicosmos]

Thanks for the tips guys!

wanderinwalker: I've thought about picking up an X-die for the .223, how do you like it? Does it really reducing needing to trim the brass?

ID_shooting: No laquered ammo in this gun, all premium factory, or my handloads. I am pretty sure it was an incorrectly sized piece of brass that caused this particular jam, as the rifle as had about 5-600 rounds through it, and this is the first jam it's experienced.

 

[molonlabe]

I have match chambers on my AR's If I do not FL resize my rounds. That is lower the die until it touches the shell holder then turn the die an additional 1/8 a turn. (no comments that is on the RCBS website) I will sometmes get the jam you mention and I need to use a screwdriver to back out the bolt from the bottom. Since I FL resize using RCBS's instruction I have never had a problem. Firing the round extracts it OK. I fired those rounds in my mini 14 with no problem.

 

[wanderinwalker]

Kamicosmos,

Yes, it does work to help avoid trimming once set properly. Beware of allowing any untrimmed cases to enter the stream though once underway. The die will turn a case with an extra-long neck into something resembling a double-radiused Weatherby cartridge. No kidding. Adjust per molonlabe/RCBS and no problems resulting. Love it because it gives me more peace of mind loading with a progressive.