Sticks Wrote:Post the lot number on the ammo. Also do a COAL measurement on an unfired round.

Unlikely, but measure the bolt overall length, and bolt face depth to see if it is a .125 or .136.

With the gas block in position (your post reads like you tried to move it) - remove the BCG and look to see if your gas tube is centered inside the receiver, and you have the correct end of the gas tube in the receiver. Inspect your gas key on the BCG to see if there are nicks or deep markings on it.

And stop prying open your action. Google "AR15 Malfunction Clearing", and "AR15 Mortaring" and learn how to do it. Two handed pull on the charging handle first, then Mortar if you still can't get it to release.

A5BLASTER Wrote:My JP 18 inch barrel did the same as yours when I first put it together the cause was the gas was cutt off to much and the bcg wasn't completely unlocking.

Check the gas block is a line properly and open it up to a lil more then half are go to full open and work down from there.

A5BLASTER Wrote:What do you mean by ( gas key).

Or you useing a adjustable bcg with a adjustable gas block?

If not and you meant you lossed the screws in the gas key for some reason that could be a problem I think, if it's a normal bcg with a fixed gas key I don't think you should be lossing the screws that hold it on to the bcg.

Might sound kind of dumb but I want to ask are you adjusting the gas with the screw that's on the right side of the gas block are the screw that's in the front face of the gas block?

Also a note of info, JP barrel's are spec's to have the gas block tight against the shoulder area on the barrel, no gap.

m796rider Wrote:You're using an adjustable gas block AND an adjustable gas key? I'd go with one or the other, but not both... You're introducing way too many variables, IMHO.

VASCAR2 Wrote:I would close the adjustable gas Bolt Carrier as much as possible and treat it like a non adjustable BC and adjust the gas block on the barrel.

Texas Wrote:The case on the far right looks as if it has been handloaded with too much lubricant on the neck and shoulder. Are these handloads or factory? If they are handloads, what is the powder, charge, and bullet weight?
Do you have a standard gas block and/or a standard bolt carrier? If you do, you may want to consider putting both in the rifle and see if you still have the problem. If the problem goes away, then replace one and retest.
Also, I did not see what buffer and spring you are using.

A5BLASTER Wrote:VASCAR2, If you close the adjustable gas key as much as possible wouldn't that be the same as useing a adjustable gas block to turn off the gas to the bcg.

I will admit I'm not totally sure how a adjustable gas key bcg works compared to a adjustable gas block.

I would think you would need to open the adjustable gas key to full power to allow it to work like a normal bcg would and then use the adjustable gas block to tame the gas down.