I was curious to know if anyone has a write up on converting a USC to UMP and the approximate cost of doing so. I've been trying to figure out what gun I want next and I decided it needs to be something pretty cool. I don't think I could afford an MP5 clone. If anyone could point me in the right direction I'd appreciate it. Even the breakdown of an MP5 clone would be awesome too. Also where is the serial number located on the gun? Would it be possible to get the part that has that first and go through the SBR process while I collect the rest of the parts for the gun over time?

Thanks.

I have a USC and all the parts sitting in my "to do" corner of my shop....just have not had the time to do much.  I have done the milling for the UMP vent slots on the forearm...thats about it

Doing the conversion yourself is very easy if you have the right shop tools, and is possible without them  (finished product may not be what you wanted thought).   I highly recommend you have HDPS (Homeland Defense & Police Supply) if you just want the work done for you.  HDPS was one of the first two or three companies offering conversion parts / services..and Ed is still doing them!  

I purchased their Stock Block... it is machined beautifully and fits perfectly.

To convert your HK USC to a look like a UMP a minimum of 5 parts are needed:

1.UMP Stock
2.Stock Axle Pin
3.HDPS Stock Block    http://www.hdps.org/htm/5-3-1.htm
4.UMP Lower
5.UMP Magazine


Here are some links to help you get an idea of what you are looking at:

Great Info Video

Scroll down to see article on conversion

http://www.hkparts.net/shop/pc/HK-USC-to-UMP-Conversion-Parts-c229.htm

Good luck     Let me know if I can help with any more info.

Blackgun_Fun

What would I need to get started? Is it the HDPS stock block? Is that the part that has the serial number? Or do I need to purchase a complete USC before I can begin the conversion? I'm just trying to figure out the starting point and about how much the total effort is going to cost me.

You need to start with a usc and figure about 1500.00 for the conversion.

RS

Thanks. For those of you that have the conversion is it worth it? Any calibers other than .45 possible? What about converting a HK94. About the same cost?

No idea about the HK94.... as for the USC/UMP:

You can do multiple caliber conversions for it, .45 .40S&W and 9mm, although the 9mm bolts are nearly impossible to get. The bolt and barrel are pretty expensive though. HKparts.net lists the .40 cal bolts for just under 600 bucks, and the barrels (225 for a 16" one and 175 for an 8" one, which are US made barrels, or just under 500 for a used german UMP-40 barrel). with 9mm the bolts are VERY hard to find....

The conversion, ergonomically alone is worth it IMHO, but Its hard to get a more kickass pistol cal. carbine. You will want to start off with an HK USC45... Then you'll need a UMP lower (I'd go with the Semi-only lower, although I think you can use any lower since you'll put the semi-auto internals into it), the stock block, and the folding stock. Plus magazines. If you register your gun as an SBR then you can get the 8" barrel too.

Now if you get the 8" barrel and SBR it on a form 1 or whatever, then you dont need to worry about "compliance" parts. If you want to keep it NON-NFA, then you will need some US made parts. HDPS makes a trigger, and magazine follower and floorplates I think, but you'll need them for EVERY magazine, which can get pretty pricey. You can go with an 16" US made barrel which would also count as a part.


HDPS is one of the big players in the USC/UMP conversion world. Check out their website HERE and scroll through. They list the whole kitten caboodle with all the parts you need (UMP lower - either semi-semi or semi-only-burst, stock block, folding stock, trigger parts (including , magazine and US made follower and floorplate) for $1375 for the FBI trigger group (semi-only) and 1395 for the "burst lower"

NOTE: the burst lower has the semi-auto parts installed, so it only 'looks' like the auto trigger group. The sear area has been filled and machined so you cant install the auto sear into it.

All you need is to add a USC and do some minor work to it (all explained at HDPS).


You can also try and look around for some already completed ones, IIRC there were some going for pretty good prices.

Thanks for the replies so far. I'll have to put together a price list but it's looking like this will cost about $2600-$2700. I don't have that kind of cash laying around right now. I guess the first step would be to save up for the USC and register it as a SBR and slowly piece together the stuff for the conversion over the 3 months while I wait for the Form 1.

keep a vigilant eye on various WTS boards, and you can get the price down considerably.

I want to say that I'm into my USC>UMP for a little less than $2k.

I bought used when I could, and also made some decent deals on new stuff.

the actual conversion process is REALLY easy, I havent done the vents nor the dye job on mine, but it doesnt really need them for function. opening the mag well and enlarging the hooks took me about half an hour. just go slow, remember you cant put material back. I used JB quick in the sear cavity,

as previously stated, the ergonomics of the conversion are well worth it, and the high/standard capacity doesnt hurt

ETA:
the stock block was the sticking point on mine, couldnt find one for the longest time. so if you are planning on doing one, the minute you find a stock block, get it.

I would recommend finding a used one.  Its an HK so its not like you really need to worry about it breaking.  You can find 2 types of used ones out there.  People who paid 2700.00 for the setup and think its worth 2700.00 and people who paid 2700.00 for the setup and realized to sell it you need to get around 2200.00 or so for it.  Just keep your eyes out.

Yep thats what I've been doing. Buy the USC and get some 10 round mags for it, then you can slowly work on parts as you get them. The UMP short barrels will work fine on the USC with the USC bolt.

I've been doing this.



I got a really good deal on a UMP burst lower because of that. It'll only shoot semi, of course, but the burst and auto markings look cool. I've saved a bunch on what HDPS and HKparts were selling them for.



 

Yeah I wrote one up several years ago when I did mine.



http://www.texassmallarmsresearch.com/TechInfo/HowToUMP/HowToUMP.htm



 

Thanks for doing that write up BTW! Along with all others as I am compiling info from you guys on how to do it right.

All I need to track down is the stock assy w/ block, UMP mags, Mill 4 slots into forend and SBR the dam thing. My O-1-2-Full lower is now 0-1-1-1 .  

Thanks for the info guys. Just one last question. After doing the conversion, is it worth it? I barely shoot my AR's since I'm not yet a member of an outdoor range and the ammo I have to buy for the indoor one is too expensive. The .22lr conversion also just isn't as fun. Since this is a pistol caliber I can at least shoot it at the indoor range I'm a member of.

That's a personal question.  It all depends on what you're looking for.  If all you want is a cheap fun pistol caliber shooter then the USC/UMP is probably not your best bet...at least in the cheap category anyway (cost of unit and cost of ammo).  If you already have a AR then a 9mm setup for that gun might be a good option.  Or, how about a WLA Sterling?  Or a Beretta Storm?  Or a Uzi?  Lots of semi-auto subguns out there that can be had for a lot less than a USC/UMP...again in both initial cost and cost of .45 ammo.  Now, having said that, get a USC/UMP and once you're over the sticker shock you'll be all smiles