dear bonanza 50,

i assume you are thinking of the wonderful 350 gr woodleigh weldcores?

strictly for the turnbolt .375 belted H&H, not the double, here is some info:

350 gr woodleigh weldcores
H4350 68 grains 2300 fps
H4350 72 grains 2380 fps
H4831SC 73 grains 2250 fps

i got all these loads from Mr Geoff McDonald of Woodleigh, a very fine gentleman indeed.

my pre-64 super grade .375 prefers the H4831SC for accuracy, but also handles the H4350 with aplomb, 70 grains for 2350 ft/sec.

obviously after i got the info from Mr McDonald, i started off w/ 10% lower loads etc etc.

somebody above mentioned 416 rigby loads:
Mr McDonald recommended these loads for Woodleigh's 450 gr. bullet in the 416 Rigby:
H4831SC 94 grains Federal 215 primer 2300 fps
H1000 100-105 grains Federal 215 primer 2100-2200 fps

i have not tried these out because i recently traded in my .416 on a dakota 76 in 404 jeffery.

by the way, this info from woodleigh is fairly current, Mr McDonald gave it to me last july (2004).

good luck and good hunting!

lapsub