Agreed with the above... .22 if you want something a bit more versatile than a .25. I've tried .177 and .22 and out to 25yrds .22 is king of the two (not tried .25 but I'm sure at barn distance .25 has to be better). I'm going to try a .20 barrel on my huntsman now to see if it works ok in barns so I can have 1 pcp for farm & field use. If it doesn't I'll just buy a .25 barrel for it, or get another huntsman in .22.... & Buy a .25 barrel as well!! Lol