Ar15 BCG doesn't look right

[VortecK1ng]

So I bought this bcg and it doesn't look right when the bolt is locked back, it looks as if the bolt is over the round in the mag and will not load when I drop the bcg. I have not actually tried it yet I haven't been somewhere it would be ok if it accidentally fired a round off. I am a beginner builder have built 3 other rifles that have all functioned correctly but this really stood out to me. Am I right to be concerned and maybe as for a refund and find a BCG somewhere else? Thanks. The 2 fist images are of the "faulty" bcg and the last single image is a diffrent bcg in the same gun.

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[bolus]

welcome!
for future building, invest in a couple of snap caps (fake rounds) which are great for testing function without using live rounds
https://www.amazon.com/Zoom-Precision-Snap-Caps-Pack/dp/B002IEE7KU

 

[Medic!]

Or use an empty mag and see if the bolt locks back.

Doesn't look like it will.

 

[VortecK1ng]

Yeah I have snap caps for some other weapons, just not this caliber yet.

It locks back just fine with or without out. I am talking about the distance the bolt is out.

 

[VortecK1ng]

I just took the pic with the ammo to paint the picture a little more clear about my problem.

Yeah I have snap caps for some other weapons, just not this caliber yet.

It locks back just fine with or without out. I am talking about the distance the bolt is out.

 

[bolus]

Yeah I have snap caps for some other weapons, just not this caliber yet.

It locks back just fine with or without out. I am talking about the distance the bolt is out.

ah cool. how does it look like from this angle. is the front of the bolt catching on the bolt hold open part (bolt catch)?

 

[UserNameInUse]

Sorry if this is a dumb suggestion because I'm not that familiar but could that be a 9mm bolt carrier?

 

[VortecK1ng]

ah cool. how does it look like from this angle. is the front of the bolt catching on the bolt hold open part (bolt catch)?

View attachment 317073

Thank you for that angle. It is looking like the buffer and or spring isn't allowing it to pull back that far... well thanks for that angle again it helped out tremendously, now I can get it to catch in the other guns now too... weirddd. Thanks again.

 

[3MTA3]

Do you have another AT-15 bolt carrier you can compare it to? If not, you could take it to a shop like Curt's and I'm sure they would be happy to let you check it against one of theirs.

 

[bolus]

Thank you for that angle. It is looking like the buffer and or spring isn't allowing it to pull back that far... well thanks for that angle again it helped out tremendously, now I can get it to catch in the other guns now too... weirddd. Thanks again.

interesting. the bolt may be catching on something. Can you post a pic of just the lower receiver?

I wonder if it is catching on the buffer retainer. That little spring loaded pin that keeps the buffer and spring from flying out of the buffer tube when the rifle is taken a part.

 

[Kruel J]

I was just thinking that as well.

 

[3MTA3]

Also, examine the buffer tube itself carefully. I purchased one a few years ago that wasn't cut square to the threads and prevented the buffer itself from being captured. It's possible that a shoulder is catching on the bolt.

 

[VortecK1ng]

interesting. the bolt may be catching on something. Can you post a pic of just the lower receiver?

I wonder if it is catching on the buffer retainer. That little spring loaded pin that keeps the buffer and spring from flying out of the buffer tube when the rifle is taken a part.

View attachment 317091

Does that look high?

 

[HB of CJ]

Pull an AR15 carrier group and compare closely with yours? That bolt face looks thin-strange? Does a case base fit into the bolt head face correctly? Like already said, (and thank you) a 9mm bolt head? Not sure. Can not tell. Correct buffer/spring combination? USGI parts? Commercial parts? So many possible combinations today. It is quite possible there may be some combo of stuff that is not working. Respectfully.

hundreds of builds. uncounted many rebuilds.

 

[VortecK1ng]

Pull an AR15 carrier group and compare closely with yours? That bolt face looks thin-strange? Does a case base fit into the bolt head face correctly? Like already said, (and thank you) a 9mm bolt head? Not sure. Can not tell. Correct buffer/spring combination? USGI parts? Commercial parts? So many possible combinations today. It is quite possible there may be some combo of stuff that is not working. Respectfully.

hundreds of builds. uncounted many rebuilds.

I can now get this bgc to lock into my other 2 rifles no problem now, that I know what I should be looking for on the bolt catch meeting the bolt.

I took the spring and buffer out and swapped it with a known working setup. Still wouldn't lock any group back properly, even with as hard as I can pull it wouldn't even have a chance grabbing the bolt head.

How far back should I be able to push the spring and buffer tube before it bottoms out?

 

[bolus]

Does that look high?View attachment 317093

yes that looks right.

The bolt is not going back far enough so that's where to start trouble shooting. so a pic of two bolts side by side will help to make sure it is the correct bolt. Then think about the buffer tube and anything that would keep the buffer and bolt going back far enough (wrong length buffer tube, something obstructing in the tube, etc)

 

[VortecK1ng]

Left one in both pictures is the new thought to be troubled group.

 

[VortecK1ng]

Buffers all look about the same.

There is a variance in Springs, the left one being the shortest and the one I am having issues with.

 

[parallax]

I am pretty sure buffer tubes and buffers come in different lengths.. some are for collapsable stocks and some are for full length A-2 buttstocks, maybe you got mis matched parts.

 

[3MTA3]

Since you have two other rifles available try the following:
New upper on known good bolt and lower.
known good upper and bolt on new lower.

That should help to isolate the problem. Fail on either above points to whichever new group is in the failed test. No failure points to the bolt.