I was also at the CBA Nationals when a fellow from out west came east and blew up his Remington 40XBR in .308 Win. on a cold PA morning shooting his favorite load of 18 grs. of H110 with a Saeco RG4 bullet which worked fine in California.
RCBS no longer publishes their cast bullet manual. The edition from the 1980s is a collector item. Olin, who makes the powder, warns against using 296 for reduced loads. H110 is nominally the same powder in non-canister grade. I've ringed M1 Garand chambers trying to use H335 in full charge loads with 150-grain jacketed bullets too. I am not inclined to experiment with spheroidal powders beyond the published manuals and that is generally good advice.