For all purposes the 470 Nitro and the 450 Nitro are twins! Both throw out about a 480/500 grain bullet at the same speed. The 470 is a very few thousanth's of an inch bigger diameter. Hardly enough to make any difference.
I have a Searcy 450NE and a JP Sauer conversion to a 450NE from a 12 ga shotgun. Both shoot great!