Thank you celltech, thats quite a list. But wouldnt a extractor need changing, as some of those, the bullet casing different? Yes, already bought a 12FV 6.5 creedmore and .223 the other day, thanks to all the help, on here. But, been thinking of getting a .308, reason being, we already have one, that costed much more than the 12FV. So, thinking that we can take a new one apart and learn a little by altering/playing w/ it. Thinking of threading the barrel for a brake. If we screw it up, we still have a second or third try, and just turn it into a 24 or 22".
Lets say, we had a factory stock .223 12FV, would that bolt face be smaller, and would be limited to the smaller dia. calibers that you listed?