Well my next gun purchase is going to be the Henry H012 Big Boy steel frame in .357. I've been hoping they would come out with a pistol caliber lever action that doesn't weigh a ton and Henry delivered. I checked it out at the fun store and the H012 is really sharp, I would take it over a late model Marlin or Winchester for sure. I contacted Henry asking about twist, groove size, and the scope mount hole spacing. They responded less than 24 hours later:
Thank you for your interest in Henry. The rate of twist is 1:16, the groove dia. Is .354 +/- .0015 and the bore dia. is .345 +/- .0015. The holes drilled on the top are not the same as a marlin hole spacing. If you are looking for a good aftermarket rear sight for it check outwww.skinnersights.com
Looks like standard .357 boolits might be a winner, which is good news because that is what I size all my .38's to. I bet the H012 will really like the new Lee C358-200-RF. I'm saving for one, already have a special envelope started!