USP 45 is larger, but it depends on the holster. I have an Odin and JM custom IWB holster for my USP 45 and USP 9. The 9 would not fit in the 45 and vice a versa. I also have a Gcode OWB XST holster that fit both the 9 and 45.
A forum dedicated to and laser-focused on Heckler & Koch firearms, Heckler & Koch accessories and the owners and enthusiasts that love them! Come join the discussion regarding HK pistols, long arms, NFA arms, HK accessories, HK history and trivia and more.