If you can find them, try cast bullets sized to .432. I have one (newer production Ballard rifling) and it even feeds my Keith SWC cast from a Lyman 429421. I size to .431 but I keep hearing that the microgrooves prefer .432. Only one way to find out. Not sure if you cast, but the Lee 200 RNFP actually drops at about 214g lubed, and mine loves them. 10g of Unique and you can shoot all day. enjoy.