H&K USC conversion to H&K UMP
If you can't find what you're looking for don't hesitate to contact us.Home of the Best Hk USC to Hk UMP Conversion using real
Hk UMP parts, this is the closest you can get to the real Hk UMP LEGALLY!
About Compliance parts for USC/UMP conversions: All conversions Title 1 (transfer like any other firearm) or registered SBR’s (NFA) done by HDPS CORP. comply 100% with BATFE regulations regarding imported parts count in an Imported Assault Rifle 18-U.S.C. section 922(r). and also rendered impossible to modify for illegal full auto.
Please if you are just purchasing parts, make sure to have your conversion done in compliance. Compliance parts for Title 1 conversions and SBR’s are available to choose the needed 3 parts.
Warning, failure to comply will render your conversion illegal living you at mercy of $250,000.00 fine and up to 10 years in Fed Jail charges. Please be safe, be compliant !
Also note that another brand of conversion that uses a lower receiver/pistol grip as one piece, original USC lower and long stick 20 rds magazine, all their parts ARE NOT made in U.S. and none of them count as compliance parts! Don’t make an illegal mistake!
See other important Warning at the end of this page.
Above is the SBR UMP clone, below are the real UMP’s
TRIO SBR UMP clones in .45ACP – 9mm – .40S&W calibers
USC to UMP stock block “B”
Disassemble sequence for Block “B” or “C”
If you already have your USC, you can ship it to us for the conversion and here is the break down in prices, you choose what you want for parts or services, turn around is 3~4 days for full conversion but you must e-mail to get in the schedule.
-NOTICE- OLD STYLE UMP lowers require some extra milling and fitting, add $20 for those old lowers.
Compliance Parts for the USC
For USC conversions For USC Kit price just add the price of the three parts you choose from the four available ( See listed barrel and stock prices) don’t forget if using a M16 or AK style folding stock, the stock will count one US made compliance part)
ATTENTION, most of the new production of HK UMP folding stocks are out of their own factory specifications, date code is – AI and forward.
If you have one of those I am able now to “fix” those folding stocks
You can see in the PICs the difference
Real UMP Carbine with stock on left, Bad stock on right
Good UMP stock on left, Bad stock on right
Bad UMP stock against real UMP carbine
Bad UMP stock against stock block B
date code on new production stock
ATTENTION, before you send a conversion in, please pay attention on your hammer first.
Hammer without a relieve in the right side will be problematic, usually they are found in the G36 lower grips and old early SL8-1, they will not work in the USC/UMP unless the relieve is made.
This photo was given to me by the BATFE Firearms Technology Branch
ATTENTION, If you are purchasing a second hand USC, make sure that the upper receiver was not milled out in order to fire in full auto like in the above photo. The receiver itself will be considered an illegal machine gun.
Before sending any USC upper receiver to HDPS CORP. for services make sure it is not illegal, in the case I receive an illegal machine gun upper receiver I will be required to render it to BATFE.
$ 40 labor to turn UMP lower to work together with USC upper
$ 30 Labor to invert white mark at USC selector if using NAVY lower
$ 20 Replace internals
$ 60 Engrave Polymer receiver for SBR
$ 85 Mill Rt. and Lt. UMP and lower vents in front receiver
$ 60 Dye Job on Upper Receiver only (Industrial Dye)

With this combo set you have everything you need to legally convert your standard USC Thumbhole Stock and 10 rounds mag to UMP Pistol Grip and hi capacity mag. All HK German parts are new, the 3 U.S. HDPS made compliance parts are already installed (steel trigger, follower and floor plate)those parts make the conversion legal per ATF rules, the lower already serviced to make it compatible with the USC upper.


ALSO, WE HAVE A MACHINE SHOP AND A REFINISH SHOP THAT WILL MAKE POSSIBLE TO BUILD YOUR CUSTOM DREAM COME TRUE WEAPON
Homeland Defense & Police Supply Corp