Bad BCG I think well maybe Need Help

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[ARCHIVED THREAD] - Bad BCG I think well maybe Need Help

Posted: 8/19/2017 3:46:18 PM EDT

I have a Colt full atuo BCG it seems it just won't work in my weapons ( Colt 6920- LMT)
Bought of the Net AR15.com.
I chamber the first round pull the trigger BANG no trouble BUT the next round gets jamed up doesn't matter what weapon I put it in same thing happens.
So I change to a different BCG works in both weapons and they both run great.
And for the life of me I just can't see anything worng with it everything looks like it should.
Thanks in Advance for any and all help.
JG10mm

Posted: 8/19/2017 4:00:27 PM EDT

[#1]

Did your inspection involve taking out the bolt from the carrier and looking at the gas rings? You've done the right thing by comparing performance between two bolts. Now, maybe start swapping the individual, internal components between those two BCG's to see when the problem pops up...process of elimination.

Posted: 8/19/2017 7:00:08 PM EDT

[#2]

If the ejector and extractor seem to function fine I would test the front carrier key screw to see if it was broken. Have you tried swapping bolts with carriers to see if it is the bolt or carrier causing the problem?

Posted: 8/19/2017 7:04:47 PM EDT

[#3]

When you say "the next round gets jammed up", can you elaborate? Does the carrier go far enough rearward to eject the first round, then strip a new round from the mag and attempt to feed it? If not, please explain what exactly is happening when you experience a malfunction. Is it the same each time?

Posted: 8/19/2017 7:34:36 PM EDT

[#4]

Does it lock open on the mag catch if you fire a single round in a mag?

If it doesn't, it probably has a gas key issue.

Posted: 8/19/2017 8:26:50 PM EDT

[#5]

Quote History

Quoted:
Does it lock open on the mag catch if you fire a single round in a mag?

If it doesn't, it probably has a gas key issue.

View Quote

Great question. Does the gas key seem tight?Can you see any leakage around the base of the key?

Posted: 8/19/2017 9:45:13 PM EDT

[#6]

Quote History

Quoted:

Great question. Does the gas key seem tight?Can you see any leakage around the base of the key?

View Quote

I would also make sure it is clear. Putting a pipe cleaner through it would verify that.

Also try to wiggle the gas key. This is a test you should be doing after every session anyways.

Another test you can do is making sure it is sealed. Put some oil around the base where the gas key and blow compressed air into where the gas tube goes into. Very little amount of oil should bubble out.

Posted: 8/20/2017 5:07:29 PM EDT

[#7]

Problem found, thanks to everyone.
The front bolt in the key was tight BUT broken off the only thing that was holding it inplace was the staking job.
Thanks again for all the help.
JG10mm

Posted: 8/20/2017 5:36:23 PM EDT

[#8]

I'm glad we could help

Posted: 8/20/2017 6:52:45 PM EDT

[#9]

Glad you got it solved.

Posted: 8/21/2017 9:15:05 PM EDT

[#10]

I had the same thing happen to me

[ARCHIVED THREAD] - Bad BCG I think well maybe Need Help

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