I have a 336cb 38-55 and my favorite load is 20 gr SR4759 with 270gr cast bullet. It doesn't quite fill the case, but is pretty close and requires no filler. This gives 1660 fps, good accuracy and really low velocity variation, which I find I get anytime I use SR 4759. This load also worked good on one whitetail this year. I cast the bullet soft enough to get some expansion. A friend of mine has the same gun and bullet mold and uses 4227 with good results and also does not use any filler. Good luck - these are fun rifles but some of these guns have bores so large that it is hard to get the bullet diameter as large as you would want and still get them to fit in the chamber. I had my chamber opened up to solve the problem. My friend did not have this issue with his.
