The reality is like most gun things, your gona have to just try some different stuff. The White .540 is 1-24" twist. So far all I've shot in mine are the 535 grain NE's, mostly because I have 6 boxes that were on sale at the Sportsmans Warehouse for $9.99 a box. With that 1-28 twist the heavier ones will probably be best but who knows, it may like a shorter bullet too. But since you have that Lyman mold give that a try, it may be just fine.