Fitting a barrel to a hinge action can be simple, or difficult. It could be done by the handy do-it-yourselfer but I don't know how handy you are.. My initial reaction is that if you have to ask it's likely you should just take it to a gunsmith. The simple ones are long enough and only require minor machining of the end of the barrel to clear. Others are too short and require increasing the length of the barrel hinge length. That's the critical length, from the half moon cut where the barrel hinges to the end that contacts the standing breach. The reason they won't retrofit is the lengthening.. The assesory barrels are made a shade long so they lenf themselves to the fitting process. A good smith can fit one but it's a bit ticklish. A shim is soft soldered to the half moon and fitted to tighten the barrels fit to the standing breach. Heat is a very real concern!