I just bought another 100 each 348 brass. They seem to be easier to find than 444 perhaps?
My favorite load so far for my '71 is:
348 Win, Browning 71, 220 Barnes FP 9 ½, 59.5 grains RE19, 0.888" 5 shot group at 54 yards or 1.57 MOA, 2,137 FPS (iron sights)
Sighted in at 3" above zero at 100 yards:
Take a 444 (from load data):
265 Hornady FNSP IMR IMR-4198 45.3 2,066