buffer weight issue

[blackholegun]

It all depends on port diameter and the load you're shooting, as well as the condition of the BCG, chamber, and recoil spring.

The Grendel was engineered to be a drop-in solution for existing AR15 lowers, but many barrels in the after-market have used different gas port diameters.

The Grendel gas ports actually seem to correspond with 5.56 gas port diameters at the different locations.

Buffer weights are primarily for countering carrier bounce on automatic-capable rifles, with a secondary function as rate reducers.

The buffer style we currently use was actually meant as a rate reducer when the Army switched to ball powders in the AR15 in the early 1960s, even though the rifle was engineered around tiny extruded powders like 8208M.

Depending on what load you shoot, your port pressure will be quite different, so it really helps to nail down what load range you primarily want to feed the system.

The extremes of that with 6.5 Grendel are 85gr on the low end for hand loads, followed by 90gr TNT factory ammo from Federal, with 130gr on the high end of factory ammo, and even heavier for hand loads.

Some ways to deal with this are adjustable gas. The easiest adjustable gas system I've seen so far is the Bootleg Adjustable Gas Carrier, which I have.

I am running SLR adjustable gas blocks on all of my builds, 2 6.5 grendel's and one 6.5 Creedmoor.
My current build is a little finicky it seems, all of the parts are new.
AP BCG
AP UPPER AND LOOWER
BA 18" FLUTED BARREL Rifle length gas
ELANDER 10 ROUND MAGS
Just a fussy combo I guess.
Tried shooting it again last and had a couple FTF.