I've heard of folks using 40 gr of RL15 with the Lyman 358009, which is a ~280 gr bullet. I've used 44 gr in my 350 Rigby, and shot a 1" 5 shot group at 100 yds. Trouble is that load was developed with CCI 200 primers, which I subsequently found will hang fire in low temps <img src="/ubbthreads/images/graemlins/shocked.gif" alt="" /> I tried CCI 250's and Federal 215's, and ignition was fine, but the groups opened up. Next plan of attack will be finding a combo that will ignite reliably and still group tight.