Just picked up a GSG (idk what model) but it looks like an MP5SD5, for less than $200.

Its for a kid to teach shooting and what not, so my first part is going to be to replace the stock with extending to make an MP5SD6 style.

Next I really wanna put a light on the end, and I love the look of the clamp mount on the suppressor, but thus far am unable to find any mounts like what Im looking for.
Everything on the market as far as clamp mounts is geared toward shotguns, too small.

Any ideas?

Thanks.