I started testing using Rl-22 and got up to 57.0 gr with the 107 gr Sierra which produced 3600 fps out of my 30" Lilja 3 groove, 1-8 twist.
Groups were running in the sub 1.5" ctc range at 500 yards and often under 1" so I tested no more.
Only load modification I have made over the years was to reduce to 55.0 gr for a velocity right at 3500 fps just to save on the fine barrel a bit. Still is shooting 1/4 moa at 500 yards consistantly.
By the way, my reamer got here yesterday for the 6.5 WSM so I hope to get it together this weekend after I finish up some customers rifles and hopefully range test it next week after the bedding cures for three days.
I tested several powder's in my 6-284 and
have to agree with fiftydriver that RL 22 is
the powder of choice for heavy bullet's,but
please dont start out with his load of 57gr.
or you could end up with a face full of barrel. I have a 29.5" pac-nor 3groove 1-8
twist and also shoot the sierra 107 mk's
my most accurate load is 50.0 gr.at 3300fps
absolute max. load in my gun is 52.5gr RL 22.
start at about 49gr.and work up from there.
R-22 or IMR-4831 get my vote with R-22 giving about 80 more FPS in my Rifle. I would start around 51 grains and work your way up 1/2 a grain at a time. If you go with R-22 get it in the 5lbs keg you wont be sorry that powder changes from lot to lot.
I must agree with you about buying a 5lb keg
of RL-22, I have 3 different lot's of it and
each lot is absolutely different. it can
drive you crazy working up a load with 1lb
and starting over when you get another lot.