First off, you'll never own an H&K UMP45 because they didnt come out until 1999 (according to wikipedia). The way the laws are now, if a full auto firearm was manufactured after May 19, 1986, it can never legally be owned by a civilian (unless you're a Class III dealer).
An H&K MP5 is a different story. They came out in 1966, so as long as it was manufactured AND registered with the BATFE on or before that date, you can own one. But itll cost you about $20,000.
Worth it? That's up to you and how deep your pockets are
Last edited by GLP Standard; October 12, 2009 at 09:14 PM.