AR-15 help

[happy1]

My buddy has a AR-15 Rock River DPMS lower, It won't eject the brass anymore. When he fires it the bolt will move back about a 1/2 in. he can eject it by hand easily enough and the brass is cold not hot as you'd expect a just fired brass to be. He sprayed CLP break cleaner in the gas tube it run out of the bore pretty freely. But hasn't taken the gas block apart. we're using hand loads Win 55gr fmjbt 26.0 H335.

Any ideas
Thanks

Paul

 

[1911Tuner]

Check the bolt carrier key to see if it's come loose.

 

[rcmodel]

Take the bolt carrier apart and see if the three gas rings are still on the bolt.

While you are at it, see if the two screws holding the gas key to the carrier are both still there, not broken, and tight, tight!

If all that checks out, put the bolt back in the carrier and extend it fully like it would be when unlocked.
Now set it down on the bolt face.

If the weight of the carrier collapses the bolt into the carrier, you need to replace the gas rings with new ones.

rc

 

[happy1]

Thanks Guys I check with him right now

Paul

 

[happy1]

Everything checked out Gas key is tight gas rings still there carrier stays where it's suppose too.
Thanks
Paul

 

[taliv]

it run with factory ammo?

sounds like you've checked the 3 usual suspects: gas key, gas block alignment, gas rings

 

[rcmodel]

Win 55gr fmjbt 26.0 H335

It seems, according to Hodgdon manual, that your load is .7 over the 25.3 grain MAX load.

Did you try working up from the suggested 23.0 grain starting load with that rifle?

rc

 

[happy1]

We tried Factory ammo today and no go, fires but won't eject.

Paul

 

[happy1]

Yes I did in .5 grain increments and no excessive pressure indications Lymans loading manual puts it at about half way.

 

[rcmodel]

Hmmm!

Take the forend covers off and see if the gas tube is pinned in place in the gas block?

Check it for kinks or a bend where it goes through the barrel extension nut into the reveiver.

Check the back end of the gas tube to see if it is scuffed up & worn on one side from mis-alignment with the gas key on the carrier.

Also, will the bolt lock open if you load & fire with only one round in the magazine?
If it does that, you have an extractor problem causing it to slip off of the empty after if has pulled it clear of the chamber.

Could be a weak extractor spring, or a broken or chipped extractor hook.

rc

 

[degunner]

has he changed the buffer weight and spring?
Is he using a normal gas tube? I had trouble with an adjustable gas tube FWIW.
Have you confimered a proper charge in the reloads / handloads?
Will the rifle cycle properly with factory ammo?
are split in the three gas rings on the bolt offset from eachother by ~60 degrees?

 

[rcmodel]

eachother by ~60 degrees?

Shouldn't matter.

They constantly move all the time and get aligned & unaligned all by themselves while shooting.

The gun should still work just fine with all of them aligned.
If it doesn't, something else is wrong with it.

rc

 

[degunner]

is the gas tube pinned in place? guy a few months back had an improperly installed gas tube, can't recall exactly but was having FTF / FTE and related cycling issues.

 

[happy1]

has he changed the buffer weight and spring?
Is he using a normal gas tube? I had trouble with an adjustable gas tube FWIW.
Have you confimered a proper charge in the reloads / handloads?
Will the rifle cycle properly with factory ammo?
are split in the three gas rings on the bolt offset from eachother by ~60 degrees?

The bolt will only move back about 1/2 inch when fired with either factory or reloads... he hasn't made any modifications to the rifle

 

[happy1]

You aren't going to believe this, but he had a couple of blown primers from some reloads he had gotten (not mine) and one of the primer cups had gotten into the gas key tube and blocked it. Maybe one in a Billion chance of that happing, a little Kroil oil and a small brad few taps with a hammer and all fixed.

Thanks
Paul

 

[FLAvalanche]

Good catch! And reason 1,423,241 not to shoot someone else's reloads.

 

[rcmodel]

Dang!
What a deal!

I would not have thought of that happening in a million years.

rc

 

[Howard Roark]

I've had this very thing happen to me twice.

 

[happy1]

Me neither rc And Howard you had it happened twice, damn.

Paul

 

[Howard Roark]

Yes, my 600 yard loads are quite hott.