Who has the Brownell's 18" 6.5 Grendel barrel? What buffer, spring, gasblock setup?

[TacBlade]

I have this barrel/ bolt. I have the standard JP Silent Spring and a non adjustable gas block. It's throwing brass at 1:30 and does not lock back after last round. I have tried all weighTS of springs that JP offers and no changes. Also added one tungsten weight to the JP buffer. I have not tried an adjustable gas block. Let me know what you are using and where your brass is flying? Thanks!

[LRRPF52]

The Brownell's 18" Grendel barrel has a .094" gas port, which is huge for a MLGS/18". Whoever did that isn't familiar with how to port a MLGS, so they need to be compensated for.

The JP SCS seems to be set up for a lightweight lo-mass carrier. Did you try any lighter springs for the SCS?

What bolt carrier do you have, and what load are we talking about?

[TacBlade]

So what is suggested that I try? I have tried the lightest spring JP offers. I have an AR15 carrier, not an M16 carrier, which I believe the M16 carrier is heavier? I am shooting factory Hornady 123gr A-Max.

[LRRPF52]

Did you try the light springs without the added buffer weight?

[TacBlade]

Yes

[LRRPF52]

Might want to try a conventional buffer and recoil spring, with an adjustable gas system. I would look at the RCA gas key before a block.

I know an 18" MLGS with .094" port choked almost all the way will run with a standard rifle buffer and rifle spring.

[m796rider]

I have this barrel, but cut back to 17". It throws brass to my 2 o'clock but the bolt does lock back on an empty mag. I'm going to try one of my Tubbs flat wire action springs to slow down the BCG a tad. All my bolt carriers are M16, by the way.

[Apparition]

I have the brownells 18". Never had any issues with it I'm running a BCM BCG, a Geissele gas block and a PSA lower kit for the spring and buffer.

[Trock03]

I have this barrel/ bolt. I have the standard JP Silent Spring and a non adjustable gas block. It's throwing brass at 1:30 and does not lock back after last round. I have tried all weighTS of springs that JP offers and no changes. Also added one tungsten weight to the JP buffer. I have not tried an adjustable gas block. Let me know what you are using and where your brass is flying? Thanks!

TacBlade -

I've got my 18" Brownell's barrel/bolt paired up with a standard rifle buffer/spring and M16 carrier. Seemed to be severely over gassed so I installed an adjustable gas block (Seekins) and all is good. Don't get too hung up on where your brass is landing.

FYI it'll drop 123 SST's on top of each other out to 200 yards. Wolf steel case, on the other hand, makes it look like i'm shooting on burst.

TC

[RAM2940]

Like said above, try a adjustable gas block, SLR & Seekins are good choices.

[TacBlade]

Will do!!!