help with 77 TMK load, accuracy

[JDBAK]

So I have a White Oak Armory 3-gun upper (med profile 18" barrel, 1-8" twist), and have been trying a few loads out.
It's not a stellar shooter, get's about 1.4" 5 shot groups with Mk262 (77 SMK), a 1.6" ish with 77 SMK with 23 grains of TAC, about 2-2.5" with 62 mil ball, and 2"-3" with 77TMK over 23 grains of TAC.

For reference, my work M4A1 with M855A1 does at least as good (usually sub 2.0" 5 shot groups) as my WOA with 77 TMK.

Does my gun just not like 77 TMK for some reason, or would switching powders likely help? Is 1-8" twist not enough?

And yes, I know I should shoot more 10 shots groups with this gun, but when it's already over 2" at 5 shots, than what's the point of burning components?

Anyway, advice is welcome. I'd really like to be able to shoot 77 TMK for service rifle competition and hunting.

 

[Formidilosus]

So I have a White Oak Armory 3-gun upper (med profile 18" barrel, 1-8" twist), and have been trying a few loads out.
It's not a stellar shooter, get's about 1.4" 5 shot groups with Mk262 (77 SMK), a 1.6" ish with 77 SMK with 23 grains of TAC, about 2-2.5" with 62 mil ball, and 2"-3" with 77TMK over 23 grains of TAC.

For reference, my work M4A1 with M855A1 does at least as good (usually sub 2.0" 5 shot groups) as my WOA with 77 TMK.

Does my gun just not like 77 TMK for some reason, or would switching powders likely help? Is 1-8" twist not enough?

And yes, I know I should shoot more 10 shots groups with this gun, but when it's already over 2" at 5 shots, than what's the point of burning components?

Anyway, advice is welcome. I'd really like to be able to shoot 77 TMK for service rifle competition and hunting.

Swap powders.


And, shoot some larger groups sizes with M855A1- 30 round groups for most lot#’s are going to be between 5-7 MOA at 100 yards from Colt/FN/DD barrels.

 

[Dave Thomas]

I agree with above advice. Try a different powder.

 

[flyinsquirel]

Unless you already hit pressure at 23, and since you already have it on hand, I’d give 24-24.5 of TAC a try at a 2.26 coal with both the SMK and TMK. That would put you in the 556 load data range.