Well I've been here... I have a 24inch barrel though. When I built my grendel I was on the 6.5 grendel forum a lot getting ideas. I have a satern custom machine bull barrel.. There was not much load data out there then as there is now. My pet load is 123gr AMAX on top of 28.7 gr of RL-15 fed match primers and lapua brass. AND brass prep is very key for this round in my experience. I dont know if you will find load data using RL-15... so use caution, but thats what I have ran for 3 years now, and it bug holes, no problems... That crunches powder a tad... its a over max load, but MY rifle LOVES IT! get right at 2500 fps on a hot day.