An alternate bullet in lighter weight and a good performer is the Speer 300 grain UniCor/Plinker. It's a tough bullet that I've used at MVs up to 2200 fps without and signs of getting frangible.
I found a sweet spot at 2015 fps, 59 grains H322, Starline case, and CCI 200 primers. SD is a little more than I like at 37 fps, but I keep my shots well under 600 yards so the vertical dispersion isn't too noticeable. (grin)
But, my favorite for the .45-70 is the Piledriver jr/H322 going 1679 fps MV.
