I will have to check the barrel shank dementions but off hand I do not see why the #1 would not be a good canidate for a .450 # 2 N.E. build. I built a .450 double in this caliber and love it and all the #1 Rugers I have built shot very well with a bit of tweeking. The one ugly spot on the #1 is the hole for the forearm screw and I take care of this with a metal inlay which can be engraved but is easy to remove if needed. If you want to see how this looks it is on the web site customguns.us under custom builds. The Ruger #1 is a clasic looking rifle and I think should be offered in more of the classic chamberings, I wish the #3 was still around also in the clasic chamberings.