BCG problem

• Aug 20, 2013

• #1

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

Just got done assembling my first AR. I'm having some trouble with a binding bcg.

The front of the bolt seems to get stuck in the barrel extension. Without the barrel things move freely. Gas tube also does not seem to be the problem. The BCG slides in fine but when it locks forward it is like heck to get it back out. Every once and a while it seems to free itself and will pull back. Any ideas?

 

• Aug 20, 2013

• #2

pwoolford

AR15's make me :-)

Jan 3, 2012

4,186

White Marsh

How tight is the bolt when just sliding the bolt in and out of the bolt carrier? I'm assuming lube makes no difference. Do you have another BCG you can swap into this gun to see if the problem follows the gun or the BCG?

 

• Aug 20, 2013

• #3

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

I have nothing to go by but it seems plenty smooth until it goes into battery. No other BCG atm.

 

• Aug 20, 2013

• #4

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

More info, I think it is catching on the little square piece under where the gas tube goes. You can see a little notch where it's hitting in the upper where it has that little half circle cutout.

 

• Aug 20, 2013

• #5

Sticky

Beware of Dog

MDS Supporter

Mar 16, 2013

4,503

AA Co

Have you disassembled and lubed the bcg? This could be part of your problem. It's easy to take apart, lube and reassemble, only takes a few mins and a few drops of oil..

 

• Aug 20, 2013

• #6

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

Nope, like I said first AR. I'll see what I have to do to do that.

 

• Aug 20, 2013

• #7

Sticky

Beware of Dog

MDS Supporter

Mar 16, 2013

4,503

AA Co

Try this vid.. it'll help you...

http://www.youtube.com/watch?v=r3uOZVl8_EY

 

• Aug 20, 2013

• #8

F

Ferg

Active Member

Aug 1, 2011

182

Southern Dorchester County

FYI, don't get slick and test the carrier movement without the firing pin... test it completely assembled until you understand how it works.

 

• Aug 20, 2013

• #9

Sticky

Beware of Dog

MDS Supporter

Mar 16, 2013

4,503

AA Co

and an interesting take on bolt carrier group lubing.. perhaps a little excessive, but seems effective.. lol

http://www.youtube.com/watch?v=AZBynDSMXP8

Personally I use Machine Gunners Lube, a synthetic moly based oil and I lightly coat all the parts, paying particular attention to the contact surfaces on the front half of the carrier. Works great for me.

 

• Aug 20, 2013

• #10

jcbvh

Active Member

Dec 30, 2012

993

Louisiana Cajun Country

These things can cause this amoung other things

Cracked or out of spec Bolt Carrier. (rare, but does happen)
Mis-aligned buffer tube.
Bent charging handle.
Unstaked gas key being loose.
Mis-aligned gas tube.

Easiest way to verify everything but the Bolt Carrier is to swap it out with another one.

New guns sometimes do this as well. Run it lubed up (wet), and shoot it.

 

• Aug 20, 2013

• #11

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

Lubed the BCG. Some improvement.

 

• Aug 20, 2013

• #12

F

Ferg

Active Member

Aug 1, 2011

182

Southern Dorchester County

You can remove the firing pin AND the bolt so you have a "stripped carrier", and make sure that it slides without binding in the upper. Just don't remove the gas key. That would either show that the carrier or gas tube was sticking or the bolt lugs.

 

• Aug 20, 2013

• #13

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

After lubing it I've been cycling it and it is slowly improving. I think I just need to shoot this thing.

 

• Aug 20, 2013

• #14

F

Ferg

Active Member

Aug 1, 2011

182

Southern Dorchester County

Now we're talking. Any chance you have go/no go gauges?

 

• Aug 20, 2013

• #15

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

I don't. This is a .300 Blk build. My preference would be to have it checked out by someone knowledgeable.

 

• Aug 20, 2013

• #16

F

Ferg

Active Member

Aug 1, 2011

182

Southern Dorchester County

Good idea. At worst, make sure you see how it locks up on a factory round... , not someone's reload or off the shelf remanufactured rounds.

 

• Aug 20, 2013

• #17

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

Will definitely do that.

 

• Aug 20, 2013

• #18

TyFromMD

Ultimate Member

Mar 31, 2011

3,804

Maryland

What kind of BCG is this? Manufacturer?

 

• Aug 20, 2013

• #19

J

joemac

Ultimate Member

Mar 17, 2010

1,561

West Point Va

I got it from Joeboboutfitters I think. I think the charge handle as well. Not sure on manufacture. The upper is LRB if I remember correctly.

 

• Aug 20, 2013

• #20

B

bitterkenny

Meh

Apr 8, 2012

547

Earth

Are there any signs of abrasion on the charging handle or on the upper receiver where the charging handle locks up? The last AR I bought had similar issues, even after lubing up the BCG. It got much better once I lubed up the charging handle and where it meets the upper receiver. After a few hundred cycles of the action, it's all fixed up now.