Need help diagnosing a problem with my rifle...

[BravoCompanyUSA]

I just looked at my rifle again. The gasblock doesn't seem to be loose. It does look like there is an 1/8" gap between the gasblock and the step up in the barrel. Is this normal?

Generally speaking, there should be a slight gap between the gas block and the shoulder of the barrel, for the ports to line up correctly. The gap represents where the handguard cap would have been if you were not running a free float. (Some manufacturers may do it differently, and I am not sure exactly how LT does it).
I can't be sure from the picture, but it looks like the gas block may be sitting a bit too far forward - if so, that would shut down (or greatly reduce) the gas system.

[Boom]

If that is a LT block, then it is to far forward.

Remove the handguard and reposition the block. Be sure to was red loctite on the set screws. I've built several rifles using LaRue gas blocks, none have sit that far forward.

ETA: I reread your first post. That block is not back far enough. There should be a gap of 3/32" to 1/8" tops. Right now you are cutting off your gas.

[RHR]

I want to add that the D&H mags are dated 11-05. I remember reading a thread on the "other" forum about people having problems with that date.
Does anyone know if that was true?

[BravoCompanyUSA]

I want to add that the D&H mags are dated 11-05. I remember reading a thread on the "other" forum about people having problems with that date.
Does anyone know if that was true?

That will have nothing to do with failure to cycle.

Mag issues are only related to feeding issues. By your description above - your mags are good to go.

[k9dpd]

it is a gas issue, follow the advice and get the block installed correctly and you should be squared away

[C4IGrant]

Your gas block is to far forward. That is your problem.



C4

[RHR]

Ok, I did what Grant suggested. Put 1 round in the mag and shot it. It locked the bolt back on the empty mag.

[M4arc]

Ok, I did what Grant suggested. Put 1 round in the mag and shot it. It locked the bolt back on the empty mag.

Did you only try this once? Or did you test this multiple times?

How did it extract when you ran this test? When you were having the problems the other day was the empty case still in the upper or was it still in the chamber?

Did the FTe look like it was trying to chamber a new round while the spent case was in the way?

[C4IGrant]

Ok, I did what Grant suggested. Put 1 round in the mag and shot it. It locked the bolt back on the empty mag.

Did you move the gas block back?


C4

[Hawkeye]

I would have to concure that the gas bolck is the issue. However, if the weapon is cycling and locking back onthe one round test, that could mean its something else. Not sure what at the moment though.....

You said you are shooting Q3131 in it now. Has there ever been any Wolf shot through it? Reason I ask is, I have had to work ona couple of AR's at work recently that the owners had been shooting Wolf through and then switched to brass cased ammo. The Wolf would run fine, but the brass cased rounds would stick in the chamber and fail to extract after just a few rounds were through the gun and the chamber heated up.