I don't think the 243 is an option on the contender. The Encore, Yes but not the contender. You can get a list of options at Fox ridge outfitters. I know you can get carbine barrels in 223, 30-30 44 Mag and many more. I have had carbine barrels in 223 and 44 Mag for the Contender. SKS I think it is handles carbine barrels for the Contender as well. I also had the carbine 45-70 barrel but that one would not be for youngsters. The Contender will not handle the pressures that the Encore frame will.