The conversion to 30-40 probably could be done. I think, however, that in such a light rifle the recoil would be severe. I have had several in 30-30 and if you reload with a 130 to 150 gr spitser bullets you might be suprised at the accuracy that can be attained with these loads with more than suffient power for hunting. I particularly liked the 130 gr loads-light recoil, sufficient power, and excellant accuracy (under and inch at 100 yds) with the unaltered 30-30 case. I scoped several of mine. Also had one sleved to 25-35. Great rifles.