the .45 muzzleloader barrels havee been discontinued, so if you see one grab it up. i shoot one, have taken a few deer with it, makes a nice rifle. They also offered a .209x50, seems i head it was to be dropped also, but it is a "step-up" profile & is a tad heavier.
i have had MGM build quite a few barrels & have been pleased with them all, in both rifle & pistol format.
in a carbine, the 45/70 was a must-have for me, i hunt the timber a lot, but i also like my .35remmy & 7x30. and the 30/30Ackley Improved, and 3 flavors of hornets. and i cant imagine not having my 25/20, and my .445supermag is handy, and....you get the point. the 'tenders make a great little rifle setup.
