Sticky BCG

AR/M4 AR General Discussion
1

So I just received my BCM BCG today and after a thorough cleaning and lubing per the helpful post here, I have ran into a problem. Y’all will probably say don’t worry about it and just shoot the damn thing and I know you would be right but I have to ask. So I tossed a mag in it and started to rapidly hand cycle a few rounds. It was slow at first but then it smoothed out. Then it happened. I let it fly home and when I tried to eject it, it got stuck. I popped open the halves and had to use a pair of pliers, very gently mind you, and was able to pry the bcg back and loose. It did it a couple more times but I was able to use both hands and then finally one but with some semi heavy pressure on the charging handle to eject the round. I am assuming it is because everything is brand new and I figure the round creates more pressure and force than I can and everything just needs some shootin. Ease my worries please.

Oh the gun, RRA A4 upper, BCM auto BCG, DD 16" M4 1/7 5.56 barrel, RRA lower, A2 stock and buffer assembly. Other than the stripped upper and lower, everything was purchased through BCM.

2

Take the bolt and remove it from the carrier.

Drop the carrier by itself into the upper and see if it binds.

If it does, you have a gas tube mis-alignment issue.

3

Please, get some dummy rounds, or snap caps for function tests. Cycling ammo, especially when having issues with a gun cycle, is asking for an ND.

Does the original bolt run smoothly? compare the two, are there any differences, especially where you see wear on the RRA?

4

No jamming up without the bolt. Cycled it 50 times.

BUT…

Also no jamming with the bolt and no round. I think something it wrong with the chamber. All the chambered rounds have scratches all around the shell about 1/8" apart.

5

There is no original bolt. All was pieced together.

6

Normal it is from the barrel extension.

7

I have a buddy who works at a shooting range and has several ARs that I plan on calling in the morning. Also odd, I just tried my brothers shrubmaster bcg and it didn’t do it but the bcg has a few thousand rounds on it.

8

User error. Trying to determine if your rifle feeds properly by hand cycling is silly. Lube it and shoot it. My bet is (as long as you’re not using garbage ammo) that it runs fine.

9

Also no jamming with the bolt and no round. I think something it wrong with the chamber. All the chambered rounds have scratches all around the shell about 1/8" apart.

This occurs during extraction of a live round. The round is tensioned against the extractor and as it clears the chamber, it cams out and contacts the barrel extension. Normal.