AR10 BS Thread

Yup I pulled rear takedown pin and split the receiver same issue

 

Weird

 

Thought it could be charging handle as the aero breach has a lot of flex in it but with just the upper i tried going slow smooth level and straight back with equal pressure nope bcg still stuck closed

 

My dpms litterally takes zero effort to lock or unlock. I tried even slow release. Something is messed up in there or debris is hanging it up.

 

Whats the gas rings look like?

 

It's currently stuck closed right now but when I took the bolt apart earlier everything was brand new

 

Ok try this, with whole bolt removed does it lock aand unlock?

 

Gas rings don’t effect manual locking and unlocking. If anything it would be the cam pin.

That said, was the barrel extension removed for the “inspection?”

Because it sounds like the clocking is off on the extension. If you can flick the bolt out of a lubed BCG, then it’s not the cam pin. Some times when people put them back (barrel extension), the alignment pin is not top dead center and a little angled.


Also, it should go without saying, but I wouldn’t shoot it like that…

 

Carrier moves freely and easily with bolt removed

I did not get a spec sheet in return with the upper i asked this was the reply 50/50 on if they even checked


Definitely not going to send any rounds through it. Looks like it's going back again. Bolt is stiff but once in and retained by the cam pin it rotates without catching or snagging. I think I've got an out of spec bolt or more likely bad headspace or bad chamber/extension.

 

imagine my glee when I found this Thread about my favorite platform. Here’s my no budget, no expense spared overtime DPMS pattern AR10 in 6.5cm.

 

Well tried to call Aero this morning to discuss over phone instead of email after 20 min of holding i had to abandon that plan. Emailed them back with my video and additional photos.

We'll see what they say. Based on additional testing I did last night I belive its one of the following
1 Out of spec bolt causing the failure to rotate fully/release from the extension
2: out of spec barrel extension includes headspacing
3 this may be a secondary issue but still believe chamber is too tight.


My biggest concern is dude said he sent back the upper in the condition he tested it in. I find that very hard to believe given the bolt locking up. Either they tested with a different bcg or knew the bolt would snag but said F it throw a ton of oil in there and send it back anyway

 

Ok can anyone answer this oddity.
I was putting the bcg back together in prep to send it back. This includes putting back the double o ring and spring into the ejector.

Bolt gets stuck only without firing pin installed

Bolt moves close to freely with firing pin in but there's the tiniest hang up a split second after pulling charging handle and bcg starts to move

 

Almost sounds like there is a machining burr inside the assembly somewhere. The firing pin may be pushing it somewhat clear of moving surfaces and keeping it from pulling back as the bolt moves inside the carrier?

ETA: If you have another BCG, even just a second bolt and pin, you could swap it out and see if the problem stays with the upper or follows the BCG.

 

I had a similar situation in a 556 BCG. It was terribly difficult to pull the charging handle. It ended up, there was a machining defect inside the bolt. Tried a new pin, same issue. Then tried a new bolt and new pin, smooth as silk.
I left the new set up in the BCG.
I ended up putting some polishing compound on the old pin and ran it in and out of the old bolt while spinning it a few times with a hand drill. After I flushed it out, the action was improved, but still a little "sticky". I checked to make sure pin exposed length was still good and it now sits in the spare parts bin for emergency service. It would have to be a pretty big emergency though. The polishing was mostly to satisfy my curiosity as to what was really happening and if I could resolve it.

 

Plenty of spare 5.56 but no ar10 spare bcgs friends have one but a good 45 min drive with today's gas cost may be cheaper to just buy a spare lol

I'm super close to just chalking this up to a failed experiment and even if Aero does respond and I send it back there's a good chance in order a criterion barrel with matched headspaced bolt while the upper is at aero

 

I’ve had nothing but issues with Aero on AR10 things, all the 223/5.56 stuff seems better made. I went with a matched bolt/barrel from Wilson. It’s worth the expense to get them matched.

 

Moving on as you’re describing, is probably the best plan rather than chasing problems.
There’s only so much anyone can do without just looking at it in person.

The headspace needs to be check with a gauge, tdc of the alignment pin needs to be verified, the bolt seems to need to be checked. You bore was allegedly tight, with little to no freebore, that in itself would require some actual gunsmithing.

Then, there’s no guarantee that I’ve seen, that you bought compatible parts, which is always an issue with at home AR builders and ar-10s.

Even if you got it working, working wouldn’t make it reliable…and it assumes a satisfying accuracy..

 

RE parts i went 100% aero precision in attempt to avoid incompatibility issues was a complete aero upper receiver and bcg not some hodge-podge of different manufacturers.

Lesson learned it wasn't crazy money since I took advantage of sales etc. So even adding semi Gucci barrel with matching bolt to really upgrade it to sub moa shooter isn't the end of the world. Just a super frustrating process to get there.

 

Uh. This will just make the gun jam. The firing pin keeps the cam pin from rotating. If the cam pin rotates it will bind in the channel. Real tough to get unstuck sometimes......

 

"Matching bolt" in AR platform is just a scam.....

If you have a barrel that requires a "matched bolt" that just means they didnt install the extension correctly.