Help my Grendel pistol isn’t accurate

[LRRPF52]

It is much easier to shoot bolt guns when going for tight groups since they don’t have a hammer swinging inside the action, followed by a lot of reciprocating mass slamming back and forth.

If you’re free-recoiling an AR-15 pistol, it won’t group.

Same is true with my lightweight AR-15 rifles. If I free-recoil them, I’ll get 1.5 - 2” groups.

When I man-up on the rifle and apply gas gun fundamentals with straight, rearward pull of the stock into my upper body, with aggressive rear bag support, I can rapid-fire ~ 1 MOA 5rd groups with the light-barreled guns, and anywhere from .3 to .6 MOA with the heavy-barreled Grendels.

Here’s an example of groups I shot rapid-fire back-to-back, starting with a loose-hold/free recoil from a field position, then hunkered down using gas gun technique:



That’s with my 17.6” Wasp profile Lilja barrel, which has a .650” thin profile under the handguard, then steps up to a .750” gas block journal, .740” fore end.

Load is 31.5gr of CFE223 under 123gr A-MAX in Lapua brass.


Here are some groups shot with my 12” 6.5 Grendel using gas gun fundamentals:



From the other 12” Grendel I built with the same type of 12” Faxon barrel from the initial group buy we did here, different shooter:



Then me with the same gun: