[USMC-F4]

Gents, I had so much fun with the first USC to UMP conversion that I just bought another USC from my local shop. This HK thing is addictive, and expensive. Since the FBI lowers and other conversion parts are just a little steep for now I embarked on a journey. I have plenty of high-cap mags (as well as the 10 rounders) just thought this would be a neat project.

Decided to expand the USC lower to accept the High-Cap Mags. Milled the USC lower, plastic welded the sideplates, sanded touched up with a bit of Brownells Alumahyde, chopped the stock, plastic welded and dyed. For the 922 compliance parts I went with the HPDS trigger, Omega Sear and delrin homemade floorplate and HDPS follower.

Took to the range, shot 10 round mags, UMP45 mags and my home grown 40 round Drum. All worked flawless. No cracks, no issues... plastic welding is an art (I am still learning) and paint does hide a multitude of sins.

Just showing off what you can do if you put your mind to it.

The speckled lower is an expanded magwell for High-Cap mags, just used the speckle look to hide the weld marks and slight imperfections. A smoother, rounded look as opposed to the 2 sideplates welded on the black lower.

Cheers!

 

[Pinion327]

Wow, that looks awesome. It would be great to find a use for all of the USC lowers floating around!

 

[57Bonus]

Great job! Just re-working the stock alone improves the way the USC looks, IMO.

 

[USMC-F4]

Thanks for the kind words. Just trying to breath some life into some discarded parts. It is like the "Land of Misfit Toys" in my workshop. Just a hobby, not a professional. I'll leave that to Ghilliebear and Chopstix Kid and others...

Cheers.

 

[vehement]

Wow it looks so good that I had to do a double take to realize it was a USC stock!

 

[fordemti]

Wow it looks so good that I had to do a double take to realize it was a USC stock!

+1!!!! Good job.

 

[Chopstix Kid]

Looks good! Tommy Bostic started doing those a couple of years ago I think.

 

[tbostic]

Nice job for sure , I finishing up 4 right now and I have a couple more to knock out that are not spoken for yet . It definitely makes for a nice option for those guys who are so concerned with a full UMP style build , but want the option of using the UMP mags

 

[NonConformist]

I was wondering whats involved with just getting the USC to take UMP mags. I dont need a full blown conversion right away, just want it to accept normal mags so I can use it for HD

 

[ptoemmes]

Sorry to awake this zombie...

USMC-F4 - late to the party, but yes very creative.

So far been unable to find any more - pics especially - about this being done by tbostic or anyone else. I kind of have a boner for the HERA Gen 2 FSC and ACR stock, but want my cake and eat it too with UMP mags and the USC "lower" in addition to the "upper" millwork for the UMP mags. Of course it might be nice to know how the HERA-USC actually works for usability, sighting, etc....working on finding that out.

Nothing against a more traditional UMP conversion and will probably end up there - sooner or later (it ain't so much the cost thing), but I have to deal with this more than four hour erection I seem to have - one way or another.

PS
Maybe there's a way to use an ACR (folding) stock on a UMP conversion (using FBI, Navy, or etc lower) with a stock block hack of some sort?!?!?

 

[shaydog]

Sorry to awake this zombie...

USMC-F4 - late to the party, but yes very creative.

So far been unable to find any more - pics especially - about this being done by tbostic or anyone else. I kind of have a boner for the HERA Gen 2 FSC and ACR stock, but want my cake and eat it too with UMP mags and the USC "lower" in addition to the "upper" millwork for the UMP mags. Of course it might be nice to know how the HERA-USC actually works for usability, sighting, etc....working on finding that out.

Nothing against a more traditional UMP conversion and will probably end up there - sooner or later (it ain't so much the cost thing), but I have to deal with this more than four hour erection I seem to have - one way or another.

PS
Maybe there's a way to use an ACR (folding) stock on a UMP conversion (using FBI, Navy, or etc lower) with a stock block hack of some sort?!?!?

Funny thats the thing im working on now, Is trying to figure how to mod either a stock block B or C And add my acr folder.

 

[ptoemmes]

I've exchanged some emails with Brandon. Here's a write-up of his USC-HERA-ACR.

HK USC Review

 

[StainlessStan]

which tac light is that?

 

[dwillHK]

I've exchanged some emails with Brandon. Here's a write-up of his USC-HERA-ACR.

HK USC Review

An interesting review, but I don't see any mention of 922r compliance. Using a folding stock or a separate pistol grip is enough to trigger the need for 922r compliance, and it looks like the only US part is the ACR stock, and one part isn't enough to meet 922r.

 

[ptoemmes]

I think he mentions the tac light is an Inforce.

It's mentioned somewhere that they replaced the barrel - presumably with a 16" HDPS (not SBR) and the trigger also from HDPS. Add the ACR stock and that's his three. Pricey. I did mention that ProMags (10 rounders as he is from the Kalifornia Penal Colony) - ugh - might make 922(r) a bit less expensive.

 

[markglad]

How many hours went into that?

 

[artfuldodger]

TBOSTIC STOCK & 922r- PLEASE HELP!

i have a quick question regarding use of the tbostic stock on a hk usc. i've read a few people talking about 922r compliance when this stock is in use, and i'm curious as to why? unless i read the incorrect version of the law, compliance is NOT necessary. please enlighten me if you have key knowledge explaining why.thank you.

 

[dwillHK]

i have a quick question regarding use of the tbostic stock on a hk usc. i've read a few people talking about 922r compliance when this stock is in use, and i'm curious as to why? unless i read the incorrect version of the law, compliance is NOT necessary. please enlighten me if you have key knowledge explaining why.thank you.

Which "tbostic" stock are you talking about? The USC came into the US with a thumbhole stock to comply with import regulations for a "sporting" configuration. If you put on a folding UMP stock, or even cut off the lower web so you no longer have a thumbhole stock, but instead a separate "evil" pistol grip, you've modified it to a non-sporting configuration that wouldn't be importable, so you need to comply with 922r so that it's no longer is considered an imported gun.

 

[USMC-F4]

For my project in the start of the thread I use an Omega US made sear and HDPS trigger. I also make my own floor plates out of Delrin, hence USA made.

More pics to follow on other magwell enlargements.

 

[artfuldodger]

Which "tbostic" stock are you talking about? The USC came into the US with a thumbhole stock to comply with import regulations for a "sporting" configuration. If you put on a folding UMP stock, or even cut off the lower web so you no longer have a thumbhole stock, but instead a separate "evil" pistol grip, you've modified it to a non-sporting configuration that wouldn't be importable, so you need to comply with 922r so that it's no longer is considered an imported gun.

i was refering to the one where he chops it and plastic welds it. what you said makes sense about converting from a thumb hole stock to pistol grip, but i hardly consider that a thumbhole, i guess technically it is, but come on bro. another technicality and silly rule, what did i expect? oh well, thanks for the explaination!