Gunsmithing Live round stuck in chamber ~ AR 10

[smschulz]

OK.
Make a long story short(er).
MAT Ten build (DPMS) had 18" mid gas that would pop primers on Black Hills, Nosler Match and extractor gashes on most all.
Installed PRI adjustable gas block, turn down gas and still problems with primers but the gas blocked helped a little.
Fast Forward.
Got new 20" rifle gas barrel w/ JP adjustable gas block and replaced 18".
No problems (no popped or pierced primers) at all with any ammo.

NOTE: FWIW only FACTORY NEW ammo used was match ammo: FGGM 168, PRU Match 168, Nosler Match 168, HSM 168 Match, Black Hills Red Box 168 Match.

Now after chambering the first round it is stuck.
I have to shoot to release.
I did not try mortaring to release it.
It just does not come out and did not have a light hammer to beat on the charging handle.
I can shoot successive rounds until the mag is empty.

So what do you think needs to be done?
PS.. the headspace was checked and verified with gauges.
Do I need to have someone work on the chamber or just polish it a bit or any insight would be helpful.

 

[BruxBarrels]

Re: Live round stuck in chamber ~ AR 10

Two quick ideas that come to mind are headspace and a bolt/barrel extension interference. Seeing that you checked headspace I would check the latter.

 

[The Lawn Ranger]

Re: Live round stuck in chamber ~ AR 10

primers stuck in the lugs ?

Might be the brass. I switched to Lake City and my Gap 10 shot without a problem.

 

[Tactical Support]

Re: Live round stuck in chamber ~ AR 10

Bullet sticking in the lands. Throat may be short

 

[smschulz]

Re: Live round stuck in chamber ~ AR 10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m14er</div><div class="ubbcode-body">primers stuck in the lugs ?

Might be the brass. I switched to Lake City and my Gap 10 shot without a problem.</div></div>

Six different brands of factory new match ammo ~ no reloads. ??

 

[smschulz]

Re: Live round stuck in chamber ~ AR 10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brux Barrels</div><div class="ubbcode-body">Two quick ideas that come to mind are headspace and a bolt/barrel extension interference. Seeing that you checked headspace I would check the latter.
</div></div>
Not sure what bolt/barrel extension interference is ~ perhaps enlighten me.

 

[smschulz]

Re: Live round stuck in chamber ~ AR 10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tactical Support</div><div class="ubbcode-body">Bullet sticking in the lands. Throat may be short
</div></div>
This is what the gunsmith guy at my range said.
He suggested to have a barrel guy use a finishing reamer in it or something like that.

 

[BruxBarrels]

Re: Live round stuck in chamber ~ AR 10

The bolt and the barrel extension having some type of interference between the two causing them to catch on each other.

 

[GunKnowledge]

Re: Live round stuck in chamber ~ AR 10

All you tried is 168gr match ammo, nice long stuff.

Toss a couple 147gr XM80 milsurp in the next mag to determine if its the bullets or the action. The shorter OAL will tell you if the lands are grabbing the match ammo.

 

[ctressler]

Re: Live round stuck in chamber ~ AR 10

"Throat may be short" This is what I would rule out first.

I have a bolt gun with a barrel that is short throated, I have to seat down factory ammo to keep my round from smashing into the lands too far and sticking. Measure your rounds at the ogive and the distance to your lands in the barrel, this should help you zero in on the problem.

 

[Edo1]

Re: Live round stuck in chamber ~ AR 10

Sounds like you've been given several possibilities. Listing to them all, it sounds like the easiest would be to pull a bullet from a loaded round and then chambered the empty case. That seems like the quickest way to tell where to focus your efforts.

 

[Sean the Nailer]

Re: Live round stuck in chamber ~ AR 10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PD nut</div><div class="ubbcode-body">Sounds like you've been given several possibilities. Listing to them all, it sounds like the easiest would be to pull a bullet from a loaded round and then chambered the empty case. That seems like the quickest way to tell where to focus your efforts. </div></div> Excellent advice, right there!

 

[smschulz]

Re: Live round stuck in chamber ~ AR 10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PD nut</div><div class="ubbcode-body">Sounds like you've been given several possibilities. Listing to them all, it sounds like the easiest would be to pull a bullet from a loaded round and then chambered the empty case. That seems like the quickest way to tell where to focus your efforts. </div></div>

OK I pulled a bullet and it chambered and I was able to eject it with out a problem.
Next step ??

 

[BruxBarrels]

Re: Live round stuck in chamber ~ AR 10

You are hard seating the bullets. Pretty much need to have the throat opened up and/or lengthened.

 

[Tactical Support]

Re: Live round stuck in chamber ~ AR 10

Next move is find the smith of your choice and have the throat lengthened.