The carbine barrels with one screw were the first produced. They are shown in my catalog #14, but not shown as "new". I don't have a #13, but they're not shown in #12. This would date them about 1986-87, I think. Calibers available were 22lr, .22Hornet, .222Rem, .223Rem, 7MM TCU, 7 X 30Waters, 30/30Win, .35Rem, 357Max, 44Mag, and .410 smooth bore. I've used a single screw for many years with no forend problems. Carbine barrels with two screws first show up in #19 (1992).
GOOD SHOOTIN', Walt :grin: