[CaseyRyback]

There are two types, the old type with the short catch and the new type with the long catch.

I just found this out the hard way.

For pistols 2005 and newer you'll need hammer part # 215870, pre-2005 hammer part # 214825. You can use the older hammer in a newer pistol if you swap out the Catch, part # 214773.

In my USP manual, and the one I downloaded form HK-USA's FAQ page, lists the part number as 214825 so thats the part I ordered. It turns out that the manual is wrong and out of date. Thanks HK.