Can't help w/ a 455, but I have a T/C Carbine w/ 2 bbls, a 17 hmr and a .223. I have a scope on each bbl, it takes about 5 min to swap them and a very few more to check the zero on them. They usually hold their zero's. I have an after-market hinge pin that's a tighter than factory fit, however. I'd suspect a 455 to be close to the same, a lot better than swapping one scope between them both..........