My 4 5/8" flat top is picky with cast. I did really well with the following. Most of these are pretty warm

260 wfn from Montana bullet works with 15.5 grains of 2400

6.0 grains of unique with a 240 plated slug

200 grain nosler jhp with 9 grains of unique. Same for the 200 hornady- right at 1115 fps.

Used a 240 keith style from someone, can't remember the maker. It and 7 grains of unique or 13-14 grains of 2400 did ok as well.

It seems to love the 200 nosler or hornady the best. If I'd true the throats, cast would do a lot better.