This is a 2 part question, aimed at anyone on here who makes/customises firearms. I have a 12g Greeener GP shotgun with a 26" barrel, it is my favourite gun, despite having a spangly Berretta 686 and a CZ550 amongst others, and it only cost me 50 quid. It is in excellent mechanical condition, so I fancy adding to it's utility by having a rifle barrel made and fitted for it (in addition to the shotgun barrel), having had it stripped down several times, I can see that it won't be rocket science, apart from the barrel the only other new part needed would be the extractor and that's essentially just an "L" shaped bit of steel. So, my questions; 1, What sort of ball park cost am I looking at to source a suitable barrel blank (I'm thinking of 45-70 by the way but open to suggestions), chambering and fitting to the action, adding a fixed forend (as per SG barrel) and, of course, proofing? 2, How would such a plan work wrt FAC/SGC? Obviously I would need to get a variation granting me a slot for the chosen calibre but what then? Is it on SGC with the smoothbore barrel on or does the whole "weapon system" transfer to the FAC? I imagine it would work in the same way as a double barrel that had a set of smooth barrels and a set of rifled, I know such beasts exist so clearly there is a way for it to work but does anyone on here know the definitive answer. Thanks for any help, in fact, thanks for any responses at all, it's all something to while away the time in Scabbywood! PS. I like the idea of a 45-70 to make it a nifty driven-pig gun with a decent reflex sight on top.