I've always heard that the ROT of the 760s in 35 REM, 1-16"(?), was too slow to work well with bullets heavier than 200 grains, so rechambers to 358 WIN or 35 Whelen were generally unsatisfactory 'cause the heavier bullets that you'd probably want to shoot wouldn't work well.

IIRC, Paco Kelly recommended heavy 35 REM loads for strong rifles like the 760, but not applicable for the Remington 8/81 and 14/141, Standard, or Stevens 425.