help with AR bcg

Discuss work on firearms; whether that is making yours from the ground up, milling an 80%, putting together a kit, or fine tuning a trigger job.
Post Reply
User avatar
doubletapp
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 110
Joined: May 20th, 2018, 8:27 pm
Reputation: 2
Location: San Tan Valley

help with AR bcg

#1

Post by doubletapp »

picked up a 10.5 pistol the other day but getting it home realize the bcg will not return to battery I think it's a gas tube issue anyone have suggestions

Thanks


User avatar
Kingjoey
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 928
Joined: July 3rd, 2019, 8:18 pm
Reputation: 5
Location: Mesa

Re: help with AR bcg

#2

Post by Kingjoey »

How far out of battery is it stopping at?
User avatar
doubletapp
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 110
Joined: May 20th, 2018, 8:27 pm
Reputation: 2
Location: San Tan Valley

Re: help with AR bcg

#3

Post by doubletapp »

right in the area of gas tube meeting gas key
User avatar
knockonit
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 3548
Joined: May 23rd, 2018, 3:23 pm
Reputation: 23
Location: Phoenix,

Re: help with AR bcg

#4

Post by knockonit »

use a black marker on the gas tube and attempt to go into battery, and see if it looses marking, i thought i had that issue on a couple units, but found the bolt that was in Bcg group was out of spec.
typically its the gas tube bent or out of alignment, but...................................
User avatar
doubletapp
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 110
Joined: May 20th, 2018, 8:27 pm
Reputation: 2
Location: San Tan Valley

Re: help with AR bcg

#5

Post by doubletapp »

The upper and lower seekins presision, the gas block and tube I believe are Yankee Hill.
User avatar
Medjay
ArizonaShooting.org Member
ArizonaShooting.org Member
Posts: 37
Joined: February 4th, 2020, 8:00 pm
Reputation: 0
Location: Earth

Re: help with AR bcg

#6

Post by Medjay »

Most commonly gas tube out of alignment with the gas key. Can come from both parts; gas tube can not be secured properly or is bent AND/OR the the gas key is not properly staked or on an out of spec BCG that has the milled surface that the gas key mounts to "off of table".

Seen both. Try another BCG that you know works and goes into battery on another in-spec gun. Then check upper receiver (upside down/flat on top rail) and make sure there's no play or movement in the gas tube. If there is then you need to break down the upper and start from the front and work back.

IF another known to work BCG doesn't work, it may be worth looking at the feed ramps as well. If the bolt lugs are being disrupted by something blocking them it'll also refuse the bolt and won't go into battery. All kinds of weird stuff can get in there.

Best of luck.
Post Reply