12" bbls and muzzle device hamonics

[LRRPF52]

Welcome. Thinking over all the ammunition I have fired through various 6.5 Grendels since 2009, to include a large volume of both hand loads and factory loads, I have never been able to match the accuracy of some of the higher-end production ammunition, particularly the Precision Firearms 123gr SMK and 123gr Scenar loads. I have been able to match and exceed the accuracy of the Hornady ammo.

Interestingly, the PPU 120gr MPT load has also been accurate when I have shot it, even though it was the lowest cost brass case option on the market at the time.

Through the 12” Grendels I built, this is what 123gr ELD-M factory does:



90gr TNT factory, 12” original group buy Faxon barrel:





Here are 2 10-shot groups from one of the 12” Grendels pushing 107gr SMK hand loads over 8208XBR:

100yds



I have data on 2x 12” Grendels I built with 2 different shooters, several different loads. I haven’t shot any hand-loads through my 12” yet, and have been shooting 123gr ELD-M factory lately.

It’s a fun little set-up to shoot, carry, pack, and easily fits in vehicles for carriage.

My buddy and I have both seen consistent MOA or better performance from them. The only load that shot outside of MOA for me so far has been the 120gr Federal OTM.