I have a M12 mod 1 clone with 1/8 twist 18" barrel.
My MK262 recipe is same lot LC brass trimmed to 1.750". Chamfered neck ID & OD. CCI 450 primer, 23.75g Varget , 77g SMK with cannelure. .003" neck tension Seated to 2.260" with a light neck crimp. Scope dial up at 600 yards shows velocity around 2800fps.
My MK262 recipe is same lot LC brass trimmed to 1.750". Chamfered neck ID & OD. CCI 450 primer, 23.75g Varget , 77g SMK with cannelure. .003" neck tension Seated to 2.260" with a light neck crimp. Scope dial up at 600 yards shows velocity around 2800fps.