Need help diagnosing a problem with my rifle...

[RHR]

I only tried once because I was in my Dads backyard.I didn't want to shoot much because of his neighborhood. That's not much of a test but that's all I could do today. Yesterday the empty case was still in the chamber and to get it out I really had to yank on the charging handle. Today it extracted fine on the one round.

I didn't move the gasblock. How hard is it to remove/replace a LaRue rail and gasblock?

Hasn't been any Wolf shot through it.

[Hawkeye]

I'm going to have to go with the gas block being the problem (unless for some odd reason the carrier key is not fully tight, though as mentioned this is unlikely) or the chamber is oversized/out of spec.

[jmart]

For your first session where you experienced the problem, would you say the weapon was lubed sparingly, moderately or liberally? What lube was used? How much time elapsed between when it was lubed and when you shot it?

[C4IGrant]

I only tried once because I was in my Dads backyard.I didn't want to shoot much because of his neighborhood. That's not much of a test but that's all I could do today. Yesterday the empty case was still in the chamber and to get it out I really had to yank on the charging handle. Today it extracted fine on the one round.

I didn't move the gasblock. How hard is it to remove/replace a LaRue rail and gasblock?

Hasn't been any Wolf shot through it.

It is easy. Remove the rail and pull it over the GB. Loosen the screws securing the GB and move it back till it hits the shoulder. Remove the screws and clean the old loctite off of them and apply some more before screwing them back in.
Install the rail.


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[Kisara]

One of the great design features of the LaRue gas block is that the rear allen hole is directly in line (and around the same size?) as the block's gas hole. Thus, aligning the barrel's gas port with the gas block is easy- Just slide the block on upside down, and look through the rear allen hole.


Its really hard to shoot macro photos with my cheap phone, but you can at least see the port position in #1, where the block was pushed all the way back. There's still enough space for slight adjustment without blocking the port.


In #2, I pulled the block forward enough so the back edge of the barrel port is even with the edge of the block's hole. That's the maximum space that should be allowed for a handguard cap, if needed.


In #3, the barrel's port is already starting to get covered by the block. In your photo, it looks like the amount of space here, or perhaps even more.


My only other guess is that the loose block may have shifted R/L enough to cause binding on the gas tube where the tube meets the gas key. Maybe it is loose enough to have moved back into the correct position before your 1-shot test?

[RHR]

I just took the rail off like Grant said. The gasblock was loose. I took the screws out wiped them off and put some Loctite on them. I put the gasblock against the shoulder, hopefully it's not back too far.

Thanks to everyone for your help.

[Boom]

Excellent post Kisara.

RHR glad you found the problem.

[C4IGrant]

I just took the rail off like Grant said. The gasblock was loose. I took the screws out wiped them off and put some Loctite on them. I put the gasblock against the shoulder, hopefully it's not back too far.

Thanks to everyone for your help.

Did you use loctite the first time you installed the GB?


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[RHR]

I didn't build the upper. I had someone build it because the Phantom had to be pinned and welded.

[C4IGrant]

I didn't build the upper. I had someone build it because the Phantom had to pinned and welded.

Hmm, well if you PAID for them to build your upper, I would go back and have a little discussion with them!



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