A question for you AR big bore guys.............

[sgtsmmiii]

My shooting buddy has a 6.5 Creedmoor AR platform rifle. After firing 5 or 6 shots, the rifle starts to have shallow primer strikes and failures to fire. Easy to fix, right? Checked to insure primers are seated to bottom of the primer pocket. Done. Checked to insure the shoulders are not set back too far resulting in short headspace. Done. Bullets seated out long to insure they are seated into the lands to force cartridge base back against the BCG. Done. Bolt carrier group changed out, not once but three times. Done. BC groups detail stripped to insure no debris retarding the firing pin movement. Done. Holding the buttstock hard against the shoulder to insure a full force firing pin strike. Done.

Now, the weirdness. After the barrel / chamber cools down, the rifle will again fire 5 or 6 shots before the light hits start to manifest themselves again.

What are we missing? I've run out of suggestions.

 

[lizzardking308]

Just a SWAG, but could it be gas port alignment?

 

[Saf3sh00t3r]

Is the bolt failing to going to battery?


What's the do this with factory ammo?

As well as reloads or just reloads?

I ask this because am having a similar issue with my reloads. The bolt after some time fails to go into battery.

One thing am going to try is a small base die to see if the chamber is just too tight. Although the manufacturer claims it's saami spec.

 

[8up]

Hmmm, like the previous post asks. Factory ammo or reloads? If reloads, what kind of primers used? What kind of trigger system you have in it. Trigger spring might need replaced, or just put in another spring to see if that corrects it. With trying 3 other bcg's with same outcome, I say start there first.

 

[Niles Coyote]

The only issue I've run into is with bolt carrier bounce. It would close and then partly come unlocked. When the hammer fell it would close but not go bang. Heat never played into it though.

 

[sgtsmmiii]

All reloads - he is an experienced handloader ( over 50 some odd years experience ). I appreciate all of the suggestions. We'll try each of them one at a time. Thanks again, gents. Several of these suggestions I'd of never thought of.

 

[Dag34]

I would double check the hammer spring is installed the correct way. They can be easily flipped and will cause light primer strikes. If that is good, then a new spring. What trigger is being used?

Have you made progress?

 

[BurnOut]

While I understand that the shooter is an experienced reloader, is he neck sizing or full-length sizing the cases when he does his reloads? Also, is this a new build, or a mature rifle that just started exhibiting this behavior?

 

[cfulback32]

"Bullets seated out long to insure they are seated into the lands to force cartridge base back against the BCG."

That could be your problem. I wouldn't do that in a gas gun. Could be keeping the bolt from freely going into battery. Might want to take the bolt out of the carrier, drop a round in the chamber, and see if the bolt can spin a little while in battery. Shouldn't be bound up.

 

[Saf3sh00t3r]

Try factory ammo and see if the issue happens. Use that as your baseline.


Sent from my iPhone using Tapatalk

 

[Scotts556]

"Bullets seated out long to insure they are seated into the lands to force cartridge base back against the BCG."

That could be your problem. I wouldn't do that in a gas gun. Could be keeping the bolt from freely going into battery. Might want to take the bolt out of the carrier, drop a round in the chamber, and see if the bolt can spin a little while in battery. Shouldn't be bound up.

I agree with this. Shouldn't be jamming into the lands on a gas gun.

 

[Yondering]

Because of the heat issue, I was going to guess a tight chamber, that gets a little tighter when hot. But it could be the long seated bullets.

 

[sgtsmmiii]

Thanks, everyone. He sent it back to the manufacturer. I'll report on their findings when it returns. Appreciate all of the suggestions.