Making my GSG-16 look like an MP5SD

First of all, do you consider yourself a proper "Backyard Bubba Gunsmith" as so many of us do? Haha. It can be a little complicated for some. There are a lot of non captive springs. The trigger group has....7 springs if I'm counting correctly. Just removing the the bolt carrier group exposes a non captive spring in the upper receiver, you can see through the ejection port. Be careful.

Of course this will void your warranty.

Anyway:
-take off the butt stock
-remove the lower receiver
-remove the safety. Little philips screw on the on selector
-open up the pistol grip and remove the bolt
-the trigger group will come out. CAUTION - Little brass bushings and springs are exposed to fall into the dark corners of the room
-it is possible to remove the philips screws that hold the trigger assembly together, pry the two haves apart just enough to get the mag safety bar out. But more than likely, the main spring will try to launch itself. Be careful.
-last step, put it all back together and function test

I did fully disassemble my trigger group. I polished the sear and a few other places. The cast metal of the small parts do feel pretty gritty.

Do not try this unless you are confident. Small springs that love to have secret parties in the dark with the dust bunnies can be hard to find. Here is the mag safety and its spring:

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Ok thanks for that! I will decide if it’s something I feel like after a few more range trips
 
Put mag safety spring in the other way, that way the mag stays in the gun tight, without that bar, the mag flops around and cause malfunction.



Second of all, if you boys put a set acrew in behind the trigger plate, it stops the trigger from going all the way forward, eliminating that 6 feet of pre travel.



Uses a 4-40 set screw, i have a bunch of those when build aero precision ar15.

Thirdly, if you have light strike, put in a 23lb 1911 hammer. It fits and IT IS a btich to put together because of the extra tension.
 
Anyone know what the threads are for the barrel and the length of the fake can?

I would love to source a fatter MP5D fake type can.
 
Set screw.

The barrel is too thin to be threaded the normal 1/2x 28. I suspect if one was to get it threadeded it has to be m9x0.75
 
Hey dude, looks awesome! For me it's the original sights you need to add. I forget what the rear adjustable apperature sight is called, but one of those and a bigger front sight with the full circle guard on it!!! Love that gun though, I'm gonna have to sell some family heirlooms and get one too!
 
Anyone know the thread pitch and length for the two rail screws (the ones closest to the rear that go into the brass threaded inserts)?

I also did the mag-disconnect removal, much nicer without it... I don't notice any mag issues and have had zero feeding issues; although the bolt does not hold open on last shot, unsure if that is related?
I can also engage/disengage the safety regardless of being cocked or not (which I like), was it always like this? Again, I'm wondering if it is linked to the mag-disconnect bar.
 
I don't notice any mag issues and have had zero feeding issues; although the bolt does not hold open on last shot, unsure if that is related?

Double check the you didn't loose the spring that is viewable through the ejection port in the side of the receiver.

(I also herd of some guys removing the loader assist tabs on the sides of the mags. It's the load assist tab on the left side that actuates the bolt hold open.)
 
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Double check the you didn't loose the spring that is viewable through the ejection port in the side of the receiver.

(I also herd of some guys removing the loader assist tabs on the sides of the mags. It's the load assist tab on the left side that actuates the bolt hold open.)


Thank you sir! That is exactly what is going on. ~Cheers
 
It retains the same way the stock sight posts do. It sits in between the two posts and you tighten down the tiny set screw. It also has two slots in it to fit around the two posts.

The front is pretty well done. I have a prototype of the rear, not happy with the aesthetics. Of course the diopter will not actually turn. I'm trying to maintain the same sight geometry of the stock plastic sight.
 
I still have a bunch of testing to do on the sights.

I am not sure how to approach the fact that the GSG-16 front sight posts are adjustable for height by changing out the post. I am considering either making my sight as high as the highest stock sight, #4 (four dots on it), and if you want to adjust for elevation you can clip the top of the post down as needed... or offering the sight in each height and having the user specify which height they want. Or sell all heights as a package deal.

Also which aperture size for rear sight is most desired? My gun came with a tiny and a large aperture insert. The rear sight I'm currently testing is a tiny bit smaller than the GSG large aperture but nowhere near as small as the small GSG aperture.

If anyone has any input I'm all ears.
 
I like what you did with the front sight. Was thinking of removing the rear sight entirely and clamping a 20mm HK drum style sight bit need to ensure the front and rear sights align.
 
I like what you did with the front sight. Was thinking of removing the rear sight entirely and clamping a 20mm HK drum style sight bit need to ensure the front and rear sights align.

So I am working on a rear to match the front sight in the picture. The front/rear will be available together. The rear is a faux drum/diopter (obviously will not spin to adjust for distance) that mounts to the same place as the stock sight and adjusts for windage the same way the stock rear sight does. The height over bore/sight geometry is identical to the stock sights.

I'm just trying to nail down the look of the rear and how to adjust the height of the front sight post.
 
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