I was wondering if anyone could chime in on the reliability and function of the USC conversions to a UMP. I am really wanting to get one, but I am questioning if they are reliable or not. Seems there is a ton of cash involved and I want to know if it is worth it. Thanks for the info in advnce.

I never even fired mine in standard USC configuration.  The grip felt fat and horrible and the stock was too long for me.  

I converted it and went to the range.  It shoots wonderful and feels as it should have from the start.  I have had no feeding problems using whatever 45acp I had on hand from blazer to Horandy personal defense +p.

just my .02

Mine eats any ammo I give it, reliable as hell!

Got my UMP45 SBR from Ed at HDPS. His builds are top notch!

Mine functions perfectly.

Haven't had one stoppage with it yet, although I haven't put THAT much ammo through it (due to our mags being pinned to 5-rounds up here )

What he said.  Mine has never failed to go bang

They rock!! I have built over 30 of them and have never received a single complaint, and mine has never ever had a problem of any kind.
I build and sell them a lot, I shipped one out yesterday and have another one for sale on GB right now that will be sold within a couple hours.
If you get serious about getting one, PM or email me and we can talk.
Steve

ugh.  UMP conversion threads are torture.  

I'm waiting on ATF approval for the transfer of an HDPS conversion to my dealer.

It's good that everybody says they work, but it's bad because it just reminds me that I'm still waiting.

Allright... You guys convinced me....

It's a humble start but its a start...

To do a SBR on a USC, can one swap barrels with ease or is it work for a professional to do? I am not familar with the process. Is it as simple as leaving it in the 16 inch variant and then after receiving your stamp putting the 8 inch barrel in it? Or do you have to leave the whole upper with your Class III dealer until you get the stamp?

Thanks and please post pics when you get it... I love me some HK Gun Porn...

Yep, just get a 6mm roll pin punch. a 1/4 inch is a little too big, it will fit into the plastic hole, but not the steel.


But yeah, strip the gun down (take off lower , take out bolt and recoil rod), bang the pin out, and the barrel comes out the back.

Mine ran flawless (Top Notch conversion)  I wish I had never sold it.

I converted mine myself and it has been 100% reliable. even with the USC single stack mags in the double stack lower.

I've got a new usc barrel that Im going to have cut to ump length when I get the SBR paperwork back.

Exactly my experience....but I can't SBR mine.....(NY)

What's the approx costs to convert one, also is there a parts list somewhere. I looked at HDPS site and I was so confused, wished it were AR simple...

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



 

The basic operating parts are never messed with, so I don't see why there would be any problems.

I agree,  Your basically taken the USC and putting it back in to the form it was actually designed.   I have heard of no issues when doing the mod except when unskilled craftsman try to dremmel the vent holes or modify the mag well.


Pricing varies on what you want done, but I'll try to help you out.   Ed @ HDPS does great work, I was very skeptical because it was such a PIA to get a hold of him, and get my rifle to him but once he had it, I had it back in a couple of days.

HDPS has some combo prices on kits for like 1395.00  you may want to check the EE and piece it together and check out Adam at HKPARTS.net

1.  You need a folding stock             165.00  - 195.00

2.  You need the folding stock adaptor  195.00

3.  HK Lower Receiver   395.00

4.  Rail kit,  Went with HDPS they are really nice.

5. Labor    $  35  labor to turn  UMP lower to work together with USC upper ––( using Stock Block B)
$  30  Labor to invert white mark at USC selector if using NAVY lower
$  15  Replace internals

$  18  Mill upper receiver to accept the UMP Mag

$  75  Mill Rt. and Lt. UMP and lower vents in front receiver

$  25  Labor to completely close with polymer the Release Lever Catch front section in the UMP lower, pin is modified to prevent slide out  and top of the fill is milled out ( this service prevent the lower to be used in full auto function by replacing the disconnector, most call it wrongly as Auto Sear). This also helps to secure and create a strong base for the front slim plastic wall that hold the strong hammer springs.

You will also need to decide on your 922r compliance parts,  Which pretty much says you need 3 more parts when you do this conversion that are american made.  I went with Eds Trigger, floor plates and followers.  

Hope this helps.

RS