New build has bolt getting stuck

[razorbackaaron]

Hi guys. I'm new here. I've read many threads over the years which has helped me learn. I appreciate the sharing this community does. I've never signed up, because I never felt I had much to offer. I'm way more of a RMPL guy. Anyway, my teenage son wants to get into long range shooting, so we just finished a project....AR10 6.5 Creedmoor build. I've built a few AR15's with success, but this is my first real problem, so I thought I'd ask you guys for any advice before I humbly take my mess to see my local gunsmith.

Anyway, here's the problem:

Parts:
Aero M5 receiver set
Wilson Combat super sniper barrel
I can't remember the BCG I got. I bought it about a year ago as I've been slowly purchasing these parts.
Ammo is Sierra match king (all I have right now)

Issue:
We have not fired this yet. We were able to charge, slide bolt forward, recharge, dry fire, ext all with success. Empty magazine held bolt open. All looked really good.
I put a loaded mag in and dropped the bolt. Seems to go all the way in just fine. That's when it stuck. Could not pull the charging handle back to eject live round.
Ended up taking the upper off and used a screwdriver to pry the bolt out, which it slid back pretty easily and ejected the round. Of course, I scuffed up my upper a bit doing this, but oh well. Repeated this 3 times.

I'm not sure if something is wrong with my barrel lugs or if its my extractor, or what. Here's some pics I took of the lugs and of the BCG/Round as I slowly slid it back after getting it unstuck.

Thanks guys for taking a look at this.

 

[bfoosh006]

Sounds like a tight chamber.

Does a round of the ammo "freely" drop into the chamber ? ... and freely drop back out ?

Make sure the chamber is thoroughly clean.
Then lube the bolt lugs sufficiently.
And try cycling the action , by hand, without a round of ammo, repeatedly ... in case the bolt lugs need a little break in, to loosen up.

And ... if memory serves me Wilson chambers tend to be on the minimum spec side. Someone correct me if I am wrong.

 

[razorbackaaron]

Sounds like a tight chamber.

Does a round of the ammo "freely" drop into the chamber ? ... and freely drop back out ?

Make sure the chamber is thoroughly clean.
Then lube the bolt lugs sufficently.
And try cycling the action , by hand, without a round of ammo, repeatedly ... in case the bolt lugs need a little break in, to loosen up.

And ... if memory serves me Wilson chambers tend to be on the minimum spec side. Someone correct me if I am wrong.

Thanks man. I read this exact suggestion a few times in my research of similar problems last night after I gave up. That's the plan when I get home.

 

[PinesAndProjectiles]

Are there any witness marks on the round to indicate what may have gotten “stuck?”

 

[rjacobs]

Tight chamber or headspace. If you are using factory ammo that's a barrel(chamber) issue.

 

[MontanaMan]

Sounds like a tight chamber.

And ... if memory serves me Wilson chambers tend to be on the minimum spec side. Someone correct me if I am wrong.

From my experience, you are right, at least on a 5.56 chambered barrel.

I recently had a Wilson Combat 5.56 barrel that would not allow the bolt to close on a 5.56 GO gauge, nor would it close on a new factory round that was .0015" below GO gauge HS dimension. It took a gauge .002" below GO gauge HS dimension to allow the bolt to close. Same / same for 3 different new bolts from 3 different manufacturers.

I sent the barrel back; waiting for another one so we'll see.

Wilson CS tried to tell me all their barrels are just fine because they're Wilson's.

Minimum is one thing, below minimum is another.....................ALL barrels should accept a GO gauge (SAMMI min chamber) & not accept a NO GO gauge, assuming an in spec bolt, & it should accept factory ammo below GO gauge dimension.

I always check HS before assembling a barrel to an upper & this is the only instance out of maybe 20 barrels that I've ever encountered an issue..................most barrel / bolt combos come in at around GO gauge + .002-.003"

FWIW

MM

 

[razorbackaaron]

Are there any witness marks on the round to indicate what may have gotten “stuck?”

I didn't see any, but will double check.

 

[celltech]

Lube the snot out of that BCG and fire off some rounds.

 

[MontanaMan]

Lube the snot out of that BCG and fire off some rounds.

Only if he knows for sure that the bolt has actually locked into battery with the live round.

MM

 

[celltech]

Only if he knows for sure that the bolt has actually locked into battery with the live round.

MM

Of course...but in the 1st picture the bolt is fully in battery.

 

[KZP]

Do you have another bolt you could try in the carrier?

 

[razorbackaaron]

Do you have another bolt you could try in the carrier?

I sure don't. I might ask a buddy.

Thanks everyone for the replies. If I get it all figured out, I'll post a response so any future searchers will have an answer.