Now I don't possess a gauge or micrometer and my eyesight is slowly deteriorating somewhat but is the barrel on the above "tapered" by any chance similar to the Mercury S barrels ?
If so, then its only slight but I've recently taken charge of a very nice example courtesy of my good Mate Mel (Chippendale) and the more I look at it, the more it appears tapered to me !
Its a .22 cal. by the way but thats probably not relevent.