I 've decided to get 22 Hornet and .410/45Colt barrels. The standard 22 Hornet Handi barrel's taper should match my existing for-end, but I'm not sure of with the conture of the .410/45 barrel. Will it fit the for-end that came with my BC Carbine, without a huge gap? Also, customer service says they will drill and tap the .410/45Colt barrel, with scope mount, for $35 extra. As an added note, Slim Line 22 Hornet barrels with and without iron sights are back in stock