I used W-760 back in the day to push the Hornady and Sierra 300 gr BTSP's to 2700 fps in one of my old 375 H&H's, thought I was in high cotton ;]
They damn sure shot great!
I compressed 4350 to the point it bulged my cases making clambering near impossible and still couldn't get up to speed with 270, 285, or 300 grain bullets.
I've been a proponent of compacting denser slower powders for a given cartridge shape from the get go, max speed, lower pressures, did you use a drop tube?
I had Gramps make me a 30 incher out of some
copper tubing he had.
