Home Forums Hunting & Shooting AR and Tactical Rifles AR10 stuck bolt

AR10 build on an Aero upper & lower with a 20" Ballistic Advantage barrel. Geisselle trigger, charging handle, and all other internals. JP Enterprises complete full mass BCG, JP Enterprises captured buffer assy.
Approximately 300 rounds through the rifle. About 7-8 times now, the bolt has become stuck closed with a live round in the chamber. Trigger releases, but there is no dent on the primer. I have to use a wood block or mallet and beat the charging handle to retract the bolt and live round. ..cannot pull it open even using two hands. This has occurred with different mag/ammo combinations and I can't see any obvious wear or binding points inside the reciever.
Any suggestions on where to start looking for this issue?
Thanks

When that happens is nearly always a brass case that's sized wrong or bulged from an incorrect crimp.

The easy way to extract is to "mortar" the rifle. Do that by removing the magazine and kneel down.
While pulling downward/rearward on the charging handle bang the butt plate into the ground with some force. The bolt carrier is only forced forward by the recoil spring, so the impact overcomes the force of the spring and the carrier acts like a shaft hammer against the bolt which jerks the cartridge out of the chamber. Because you are pulling down on the charging handle any movement rearward of the bolt is not allowed to go back forward and "re-jam" the shell.

Note: If you have a telescoping stock collapse it all the way 1st before doing this .

After you pull the stuck round, what kind of markings are on it?

Rifling marks on the bullet?

Marks on the neck or shoulder?

Might need to paint a few rounds with a sharpie, cycle them by hand and see where they are hitting.

Thank you for that tip, I'll try the " mortar" method next time. It's a non telescoping rifle length stock

I didn't notice any markings on the bullets or shoulders, this is what has me so confused. I'm loading to mag length , minus. 002
I initially thought it was a tight chamber since I've experienced similar problems with an M1A. So I loaded up a test batch using a small base die and had the same failure.

factory ammo is OK?

Headspace is checked? I usually buy the bolt/ barrel from the same guy.

Check the case length too. I had that problem with soft Hornady brass in a grendel after just a few loadings. Once I trimmed the cases it was fine.

Bb

Bing Bing.. this happened to me also.

funny part is this profile has been to let himself known that he is genius on everything. and it comes out he's having such simple issues and from California this is [bleep] hilarious

Thanks for the insightful reply. Are you angry because your goat rejected you this morning or because your EBT card was denied at Dollar General? Either way, I hope you have a great week.
GfY

you're gleaming intelligence on what you know about people just come shining through don't it... not sure yet which your other profile was that got ran off but I can see you're still butt hurt about that.

Pretty easy to spot the reincarnated...

The real question is - who were they in their previous life. Hummmm

I'm not trying to sell anything but a Hornady comparator opened my eyes to some sizing issues I was having. I already had the electronic calipers so my investment was small. I get the feeling that the op is not squeezing down his brass enough while resizing.

kwg

Measure fired brass.

And several times around the circumference.


Egg shaped chambers can cause these issues.