PythonHunter, I just bought my first Contender very recently and after scouring the web in search of barrels and parts, this is what I found. The most common vent-rib pistol barrels are chambered in .45/.410, and in 10, 12, and 14" lengths. There was a .44 mag vent rib barrel, though it appears uncommon, as I've turned up only one in 12". The sight setup for the vent rib was either an abbreviated ramp front sight or bead, and a notch rear. Also extant are iron-sighted "hotshot" barrels in .45 Colt, .44 Mag, and .357 Mag., that featured a removable "choke" extension, whereas the vent-ribbed barrels had an internal "choke". Hope this helps.