[Tomtep]

This might sound a little strange, but I am asking anyways. If I put a UMP lower on my USC, do I have to modify the USC to use UMP magazines, or can I continue to use the USC magazines. I live in a state where I am restricted to a 10 round magazine, therefore I am not interested in using the UMP magazines. Thank you.

 

[fordemti]

You could have tbostic modify the factory USC lower to look more like a ump stock and continue using the USC mags. Not sure how those 10 rounders would work in a ump lower. They're a single stack design.

 

[Tomtep]

Yes, that is an option, but I still have the fat USC grip rather than the nice UMP grip. That is what I am trying to get around.

 

[The_Crow]

The USC mags can be used just fine. They will be a little slow going in cause you will have a narrow window to insert them but you are good to go.

 

[AviatorDave]

Also, even if you get the mag opening widened to UMP width, the USC mags still work just fine. I haven't tried purposely pushing them to one side in the UMP lower to see if they fail, but it's not hard at all to insert them more or less centered in the mag well and they feed with no issues.

 

[kabob]

It's annoying to center in there and the USC mags will wobble but they do lock in and feed fine. Just make sure you always shoot offhand.

 

[F22_RaptoR]

You could also go and use the HERA Arms stock conversion, adds a UMP folding stock and nice grip to the USC trigger group and receiver (no mods at all). Keep in mind your 922r compliance parts, you would need IIRC 3 US made parts to comply...

Otherwise, on a full USC to UMP conversion I've heard to guys using little stick-on chair "pads" (used to protect a wood or tile floor from chair legs scratching it) to act as spacers on the mags. They need to be 1/8th of an inch thick on each side, but are supposedly completely hidden and non permanent.

Something like these:

Furniture Glides Self Adhesive, 3/4" # FE-50111 by Mintcraft

not sure if those will work, but you should be able to find them at your local hardware store no problem.

 

[kabob]

I don't know about a "nice grip" with the Hera Arms folding stock conversion. It uses the same square, blocky grip from the factory USC.

 

[amlew]

The Hera stock does come with it's own grip. Although it is of a larger overall diameter in comparison to an authentic UMP grip, the fronstrap is rounded and it is definitely a more comfortable grip than the original USC. It does present 922r issues, but personally speaking, that is not an issue for me

Hera GmbH Splash Page

 

[fullmann]

The USC mag will work fine. I used my UMP like that for quite a while before I began to horde UMP mags.

You could most likely fashion a spacer to get it to fit in there a little tighter. I was contemplating acquiring another USC mag and doing this for a 'bench' setup.

 

[Tomtep]

I was looking at the Hera Stock, but it looked to be as big as the USC grip, but if it is smaller I would be open to that option, but would need to use the fixed stock as I am not allowed folding stocks in my state so I would need to pin the stock if I did go with the UMP lower. I am aware off the 922 compliance issues, and would swap out the necessary other parts.

 

[USMC-F4]

You could also go and use the HERA Arms stock conversion, adds a UMP folding stock and nice grip to the USC trigger group and receiver (no mods at all). Keep in mind your 922r compliance parts, you would need IIRC 3 US made parts to comply...

Otherwise, on a full USC to UMP conversion I've heard to guys using little stick-on chair "pads" (used to protect a wood or tile floor from chair legs scratching it) to act as spacers on the mags. They need to be 1/8th of an inch thick on each side, but are supposedly completely hidden and non permanent.

Something like these:

Furniture Glides Self Adhesive, 3/4" # FE-50111 by Mintcraft

not sure if those will work, but you should be able to find them at your local hardware store no problem.

Gents, pads work fine... I used them on USC 40 round drum mags to fit in the UMP magwell for test. You can always sand a little off each pad to get the perfect fit with no wobble. Or you can convert the stock to the following (I enlarged the magwell to fit the UMP mags, USC mags still work fine.} Make sure you follow 922r and get the compliance parts. Cheers!

 

[Tomtep]

Gents, pads work fine... I used them on USC 40 round drum mags to fit in the UMP magwell for test. You can always sand a little off each pad to get the perfect fit with no wobble. Or you can convert the stock to the following (I enlarged the magwell to fit the UMP mags, USC mags still work fine.} Make sure you follow 922r and get the compliance parts. Cheers!

What kind of stock is that?

 

[Lohe]

What kind of stock is that?

USC stock, modified and plastic welded! Tbostic and Chopstix Kid both do it, I think!

 

[USMC-F4]

USC stock, modified and plastic welded! Tbostic and Chopstix Kid both do it, I think!

You are correct sir! Just took an extra USC stock, made a few cuts with a jewelers saw, sanded off the rough edges and finished it off with a Dremel with a fine sadpaper drum. Use the dye sublimation process to go from classic grey to black. The plastic welder used was a Harbor Freight special... but it works fine. You need to keep all of the material you cut from the stock as that is what I used for the "plastic welders rods". Solid as a rock, you just have to take your time. Enjoy!

Remember to use 922(r) parts if you mod the stock. You are changing the USC from a "Sporting Arm" with the thumbhole stock to "non-sporting" with the hack.