Mine seems to like a Lyman 311291 cast from wheelweights and sized to .310, but different guns will show different preferences for cast boolits.......... makes a good starting point though. You will need to slug your barrel to get actual size and then size the bullet about .002 over the barrel groove dia. For what it is worth, the micro groove barrels will shoot cast boolits every bit as well as the cut rifled barrels, it all relates to proper size and finding your rifles preference.
