I had origionally had problems with deciding which action to go with.One is a 1875 marge framed martini 577-450 artillary carbine or use the remnants of a greener MKIII police shotgun. That one has all the wood and the receiver is in better shape than the 1875 martini plus I could reperpose the origional buttstock and forend. Then the light in the head came on and said maybe my Ruger #1 in 45-70.I believe the barrel shank thread is 16tpi. Problem with the ruger carbine is that it is so short and really does not look right. If it were a tropical rifle then things would be different. But money at this time of the year and had to shell out some heavy bucks for a new kubots L3800 tractor with front end loader and 5'bushog to cut the grass in my back section which is starting to look like scenes from the "the lost world" Thanks for all your tips and suggestions. Frank