UMP/USC conversion

[RONNIE77]

Thinking of buying an HK USC, and converting it to a UMP.
Has anyone done that? or know someone who had it done?

Step one: Buy a HK USC (black in color)
Step two: Change the stock and lower handle (switch over trigger group)
Step three: Have it registered as an SBR
Step four: Have a smith cut and thread the barrel or buy a UMP barrel?
Step five: And totally optional, which I will opt to do, is add a can.
Step six: Have fun with it.

Is this about right?

[WhiteFeather]

The company in link used to do conversion and might have some helpful info you about what or how to do it. Hope this helped.

http://www.tacticalexcellence.com/whatisit.html

The HK USC to UMP conversion is no longer available from Tactical Excellence Inc.

This page will continue to be posted in one form or another to document what was considered by many to be the best USC conversion available.

Our thanks to all that have purchased HK USC to UMP conversions.



This Conversion is for the HK enthusiasts who wants as close a copy to the HK UMP as they can get. All key HK parts and minimal modifications. If you want the best, this is it.



Conversion Description

Tactical Excellence can take your HK USC and make it more like an HK UMP.

We do this by adding an HK UMP Lower assembly and stock to your USC. This is done with our specially designed rear conversion block. The block, made from 7075 aircraft grade aluminum, attaches the UMP lower to the USC receiver and has a hinge and latch assembly for the UMP stock.

With this conversion you now have a comfortable pistol grip, a folding stock, and use UMP high capacity magazines.

No Tools required to field strip. With this conversion you no longer need to use the USC tool to field strip your rifle. This conversion uses a Steel attachment bolt with a sling loop which adds a receiver sling point like the HK UMP. Field stripping is made simple. Remove this Sling loop / Bolt with your fingers and the entire lower swings away allowing the recoil spring and bolt assembly to be removed.



Conversion Requirements

Tactical Excellence does not supply any HK produced parts for this conversion. All USC and UMP parts required must be obtained from other sources unless we state elsewhere on the web site that we have some for purchase.

The following is required for the conversion:

HK USC receiver (may not need to be sent for conversion, see Conversion Options for more information)
HK USC fire control parts (USC lower can be sent and we will remove parts)
HK UMP Lower assembly (any "new style" variant. See Conversion details for more information) Click HERE for style difference information. We no longer do conversion work on "Old style lower receivers.
HK UMP stock
HK UMP Magazines (need only to be sent if customer is doing a Non-SBR conversion and wants us to install U.S. compliance parts for them or wants us to inspect magazines for them)
Customers wanting to change their USC to caliber .40 S&W will need to also have the following:

HK UMP .40 S&W bolt assembly
HK UMP .40 S&W barrel
Customers having an SBR conversion done will need to supply a copy of their approved ATF Form 1 or Form 4 before their finished conversion can be returned to them. Approved forms are not required to begin work.



Conversion Details

The following is what is done with your parts to complete the USC to UMP conversion:

USC Receiver

The USC receiver will have a little material removed around where the magazine seats for proper fit of the UMP magazine. Customers may also option to have vents milled into the forearm of the receiver and the receiver dyed black to better resemble a UMP.

UMP Lower

Any "New style" variation of UMP lower receiver can be used with our conversion. (Click HERE for style difference information. We no longer do conversion work on "Old style lower receivers.) The UMP lower receiver will have the front hooks modified to fit the USC receiver, a small locking tab removed, and a block permanently installed where the Auto Sear would go. Your USC fire control parts will be installed. 4 position lowers and 3 position lowers with burst will have a small notch added to the holes the selectors goes in to allow use of your USC parts. This notch is not visible when lower is assembled. 3 and 4 position lowers will have the USC left side selector remarked to line up with the UMP pictograms. UMP left selectors are not compatible with the other USC fire control parts. The right side UMP selector will be used as this part is the same as the USC but only marked different. You will not be able to move your selector past the semi-auto position to a full-auto or burst position. Only customers having a Non-SBR conversion done will have a U.S. made trigger installed.

More information on UMP lowers

All UMP lower receivers are designed to use an auto sear no matter what fire control configuration they may be. In all modes of fire, the auto sear is used to keep the hammer cocked until the bolt is fully closed. This allows the gun to fire in it's various auto modes and in semi-auto the auto sear acts as an added safety. There is no provision on the USC for the auto sear so the USC uses other parts for added safety that semi-auto only UMP lowers do not have.

Using semi-auto UMP fire control parts without an auto sear removes a level of safety designed in at the factory. Using USC fire control parts keeps that extra safety.

This is why we install your USC fire control parts into your UMP lower with this conversion.

UMP Stock

The UMP stock will have no modifications made to it.

UMP Magazines

Customers having an SBR conversion done will have no modifications made to their magazines.

Customers having a Non-SBR conversion done will have the base plate and follower replaced in their magazines with U.S. made parts. Parts for 3 magazines are included in price. If you need parts for more then 3 magazines we can supply needed parts for an additional cost.

[JayBell]

as noted the biggest problem with the USC - UMP SBR conversion is finding someone to do the conversion.

nobody even makes the non SBR conversion kits for the USC for a while now as the USC hasn't been imported for ages now...some are still available, but no new ones coming in.
they werent that popular.

A UMP barrel can be installed, but most UMP barrels i have seen have a 3 lug arrangement on them.

better to get the USC barrel chopped and threaded to fit whatever can you plan to use.

good luck on finding parts to do the conversion, this is why i converted a 9mm IMI uzi to 45 with a grease gun mag conversion instead of doing a USC.

[forceinPA]

black USC are now being imported and sold in the U.S.

[JayBell]

huh, havent seen or even heard of one for sale for about 2 years.

earn something new every day.

frankly, if I wanted a 10rd 45 carbine i'd buy the Beretta

[RONNIE77]

huh, havent seen or even heard of one for sale for about 2 years.

earn something new every day.

frankly, if I wanted a 10rd 45 carbine i'd buy the Beretta

Well, I saw a few completed conversions for sale on gunbroker. I guess they were just refinished in black.

[sluggie24]

UMP barrels, conversion kits and USCs and converted UMPs can all be found on Gunbroker. You can also contact http://www.hdps.org since they still do conversions and make parts.

[RONNIE77]

UMP barrels, conversion kits and USCs and converted UMPs can all be found on Gunbroker. You can also contact http://www.hdps.org since they still do conversions and make parts.

Very helpful, thanks for the link.

[RONNIE77]

frankly, if I wanted a 10rd 45 carbine i'd buy the Beretta

Yeah, but it wouldn't be half as cool as a UMP.

Other than the Kriss, which I don't really like, the USC is the only other .45 acp carbine thats appealing to me (Of course, with the barrel shortend and a UMP conversion kit on it). Oh, and the conversion kit takes the UMP Hi-Cap mags.

[forceinPA]

they come up on sturm every once in a while. I can get them thru lipseys or lew horton from time to time. At least they made them in black... They are also importing the g36 copy, i cant remember the name of it.