Fte, ftf bca 20" grendel.

[montana]

I'm guessing you're close enough not to be a problem. The problem with specs is that a person can narrow their focus on them instead of seeing the entire process. I have an older TDP picture from 1970 showing the spec being .1805 to .1813 If a part is over of spec on one end, but under spec on the other those parts will function perfectly.


If your rifle is running that close to the edge to cause a problem, then you have other problems.. It can be a combination of issues that can create short stroking..Over gassed rifles will also have poor ejection and have similar problems. If your rifle is holding open on the last round reliably, you probably don't have an under gassed issue. It is hard to access a problem without knowing all the details..

[bjmac]

No, it holds open on the bolt body half the time. Which i thought was weird because i don't get feeding jams. One fte. Only one time did it cycle... the others were empty chambers... rack and fine. It's very odd. It shouldn't be happening which is why I brought up me not shouldering it. The only thing I can wrap my head around.

[montana]

No, it holds open on the bolt body half the time. Which i thought was weird because i don't get feeding jams. One fte. Only one time did it cycle... the others were empty chambers... rack and fine. It's very odd. It shouldn't be happening which is why I brought up me not shouldering it. The only thing I can wrap my head around.

So it is short stroking. Do you have another bolt carrier that is known to work you can try?

[bjmac]

So it is short stroking. Do you have another bolt carrier that is known to work you can try?

I do that will have to be my next move. Unfortunately it will be months away unless they lax the restrictions at a local indoor range.

[montana]

I do that will have to be my next move. Unfortunately it will be months away unless they lax the restrictions at a local indoor range.

I think that is your best move next to see if it is your bolt carrier or gas port size. I forget most people don't have an outdoor range 5 minutes away to function test problem rifles....

[LR1955]

BJ:

After all those checks, next I would look at the buffer and buffer spring assy.

If I had a problem with an AR that I couldn't fix, I would get it to Montana or LRRP52.

LR-55

[LRRPF52]

So I got home and checked it all out. Everything looks good to me. The only thing I did was drill the gas port to 3/32. It was only a tiny bit smaller maybe a couple thousand. There was an insane amount of carbon for very little shots taken i only shot wolf and hornady black. Weird. Any other ideas?