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Can I put a G36K stock on my USC/UMP ?

6K views 15 replies 7 participants last post by  omega21 
#1 · (Edited)
I really like the look of the G36/G36K stock better than the UMP (HK or B&T) stock and infinitly more than an AR or ACR stock.



So I want to replace my current UMP stock with one or maybe put one on my next USC to UMP conversion. Problem is that the G36 stock has 2 hinge points versus the single (large) hinge on a UMP stock.

G36 stock


UMP stock


And the HDPS stock block B is designed to accomodate the large center hinge point on the UMP stock as shown below, thus will not accommodate a G36 stock...





I thought the "home made" run of ACR adapters made by LeeMajors would be a good alternative to the HDPS block, but they are sold out:
http://www.hkpro.com/forum/hkpro-gr...dapter-direct-acr-stock-instead-hk-stock.html

They look like this, so the appear to be compatible with a G36 stock, but who knows for sure...






My concern with those adapters is actually on the locking side - as it's not clear that the Buttstock Locking Piece from the G36 stock would interface properly with that adapter (where the blue arrow is pointing inside the red circle)



Now, HKParts has a G36 Demilled Rear Receiver Section that I suppose could be fuzed onto a UMP, but that item is out of stock.
https://www.hkparts.net/shop/pc/HK-...eiver-Section-With-Stock-Hinge-62mm+-p743.htm

So the only option I can come up with is to buy one of these $295 HDPS SL8 to G36 stock blocks...





...and then have an expert like @tbostic (Tom Bostic) or Joe at Dakota Tactical (@Chopstix Kid) magic fuse the stock block into the USC upper receiver, perhaps with some metal plates and brackets for support similar to SMGLee's work on an SL8 in this 2007 thread http://www.hkpro.com/forum/hk-long-gun-talk/63491-hk-sl8-v4-0-tbostic-gen3-conversion-pix.html and pictured below







Any thoughts on these or other options that would allow me to mount a G36 stock on a USC/UMP Conversion?
 
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#2 ·
Well if you want one of the UMP adapters that Lee Majors made I bought one a long while back with the pin and never used or even mounted it. Give me a PM and let me know.
 
#7 · (Edited)
#8 · (Edited)
@omega21 - I hate to be the bearer of bad news but the Lee Majors ACR/UMP stock adapter won't work with the G36 stock, I think even with heavy modification. The angle of the ACR stock hinges are canted forward 10-degrees so that when the stock is folded it clears the ejection port or the ACR for shooting the firearm with the stock folded. HK designed the G36 so that cases can eject through the G36 stock when folded, so it folds straight. The hinges don't mate up correctly as well.







 
#9 ·
@omega21 - I hate to be the bearer of bad news but the Lee Majors ACR/UMP stock adapter won't work with the G36 stock, I think even with heavy modification. The angle of the ACR stock hinges are canted forward 10-degrees so that when the stock is folded it clears the ejection port or the ACR for shooting the firearm with the stock folded. HK designed the G36 so that cases can eject through the G36 stock when folded, so it folds straight. The hinges don't mate up correctly as well.


That looks like a simple job for the dremel... just kidding! Thanks @Mr.Maim So what I'm not clear on with your post is whether or not the G36 stock CAN be mated to the UMP at all. Obviously needs a different way to connect to the receiver than the LeeMajors block, but does the 10 degree angle preclude some other solution. Any thoughts on what else might work?
@Oicani - thanks for the pic. I remember the mess you made with that plastic weld job. This is Tom Bostic level stuff, so I wanted to explore options before going to see the Oracle at Bostic.
 
#13 ·
#14 · (Edited)
Again I am the bearer of bad news. It doesn't appear that this is going to work with a G36 stock mainly because the UMP stock is several millimeters wider at the base than the G36 stock. That means that when the stock is hinged (you'd have to modify the hinge on the G36 stock a bit for it to work) the release button wouldn't reach the release striker on the stock base. The stock would also be misaligned with the receiver though that'd be a minor annoyance.

G36 on the left, UMP on the right. Notice the difference in widths (below)



Hinge configuration is different. G36 stock and HDPS UMP adapter base (below)



Lining up the G36 stock with the bottom of the HDPS UMP base so the latch lines up correctly, the G36 stock base is taller than the UMP base (below)



G36 stock lined up on hinge side. Not enough width to line up the push button release of the stock to the striker on the base (below)
 
#15 ·
I think that your idea is a good one. The G36C stock with the cheek riser would be great on the UMP sporting a lower 1/3 co-witness mounted Aimpoint T-1.

Two thing would need to happen:

1) Someone would need to make a new stock block like the Lee Majors ACR or HDPS UMP blocks, designed for the G36 stock

2) The G36 stock would need to be shaved a full centimeter off the top, possibly exposing the gap in the rear of the stock​
 
#16 ·
Regarding #2 - the alternative is that the stock block is designed so that it mates up correctly at the higher height of the G36 stock. OK, I don't see anyone making a stock block specifically for my G36 stock fantasy... I'm sure Tommy Bostic could make something happen but I don't have the cash for that right now. Thanks for bursting my bubble @Mr.Maim and thanks to everyone else for your input.
 
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