Gas Block Adjustment

rchaas

Well-Known Fanatic
Joined
Jul 28, 2012
Messages
146
Location
Tulsa
I have a new (to me) AR 15 that has an adjustable gas block. I am new to AR's in general, but trying to soak up as much info as possible. One thing I can't find much info about is how to setup and use an adjustable block.

Right now, mine is open "all the way" (per the previous owner) but the question is, what are indicators that would suggest that I need to make an adjustment in gas flow?

Thanks!
Robbie
 
Register to hide this ad
Somebody once told me to close it way down, then get an empty mag with one round in the chamber, fire a round and see if the bolt locks back. If it doesn't, open it up a little and try again. Do this until the bolt locks back on an empty mag and you should be g2g. this is all second hand info from Wall.
 
Somebody once told me to close it way down, then get an empty mag with one round in the chamber, fire a round and see if the bolt locks back. If it doesn't, open it up a little and try again. Do this until the bolt locks back on an empty mag

I go another quarter of a turn. People cut this way too close.
 
Somebody once told me to close it way down, then get an empty mag with one round in the chamber, fire a round and see if the bolt locks back. If it doesn't, open it up a little and try again. Do this until the bolt locks back on an empty mag and you should be g2g. this is all second hand info from Wall.

Yep, this is correct. When you adjust the block, use the wimpiest ammo you anticipate shooting. Once the mag locks back, give it a little more gas (1/4ish turn more for JP block) for reliability when it's cold outside, someone puts mud in your rifle, you've done something stupid like not lube your rifle before a big match, etc.
 
Usually you can start with it at least 2 1/2 turns from bottomed out. Then back it out more from there.
 
Back
Top