20" load recommendations

[vanguard138]

I just had a new Grendel put together. It is a 20" wirh a Warp brake, ss bolt, AA upper/lower with CTR stock. Also, it has a rifle lenght gas tube.

I think it is under gassed as it will not cycle the 123 gr SMK or 123 gr AMAX I have loaded for my 18".

Any recommendations for loads for these two bullets b4 I start playing with them?

I am using 27.3 gr of H335 for the SMK and 28.5 TAC for the AMAX on the 18" which has worked well in that rifle.

Hope it is not anything more serious.


Thanks:-)

[LRRPF52]

What's your gas port diameter, and what buffer weight are you using?

[vanguard138]

LRRPF52,

PM sent.