I've been content with the same load in my rifle since the early '90's , until the last couple of years. Barnes X's (270 grn.)96.5 grns. (extremely compressed)of RL 19,giving 2880 +fps.The load gave "so-so" groups, 5 shots into 1 1/2 to 1 3/4 inches. And, has never failed to do what it was supposed to do, kill very effectively.
But, with the introduction of the triple shocks and about a year ago RL 17, it was time to develope a new load.
Early results with limited testing are promising! It looks as though velocties are topping out at approx. 2960+ fps, before starting to show pressure signs.The first day of testing showed the best 3 shot group at 0.41".Day number two, with a shoulder " a bit tender" the final two groups would place two rounds nearly touching then throw the third, opening the groups to 1 1/2".
I'm not sure if it was "operator error", a dirty bore, I had passed the "sweet spot", or a combination of all three. Future testing is in order! But, if I can only launch them at 2990 fps, I guess that I can live with that!!
memtb

I'm assuming you are talking 375 H&H Ackley Improved?

Steelhead,
Yes, I guess I kinda had a "brainfart". Sometimes what I'm thinking, don't make it all the way out to the recipient! memtb