Here's one I got a few weeks ago, of course it's not minty like the one Bill got and posted here a couple of months ago as it is a bit rough but it's still neat.
When I first got the launcher I put it on a T-38 rifle and it really made the rifle/launcher combination a bit heavy and awkward so I was curious if it would fit on a T-38 carbine and as you see it does.
The launcher on the T-38 carbine is much lighter and easier to handle and I wonder if they actually did use the launcher on the carbine also as it would be a lot handier and easier to use as a grenade launching platform? I don't see there would be a problem as the light US M1 carbine was used to launch grenades so I don't see why the T-38 carbine couldn't be used. I bet you might even get a little more range/distance out of the shorter barrel which produces more muzzle blast/force?
As far as shooting the 100, I have made grenade launcher blanks and shot tennis balls out of the Lee Enfield rifle equipped with a cup type launcher in the past which was a "ball" . But I think there might be a problem shooting objects out of the 100 unless you are out in no mans land as you are firing a live round up in the air which is a no no and dangerous unless nothing is in front of you.
However I bet blanks would work in it like it does in the Lee Enfield as basically the principal is the same only instead of the gas going straight in the cup like the Enfield it just channels up and into the cup. Mmm, I may have to try that. Golf balls would be perfect to try, they are just a bit undersize but could be patched for a tight fit and I think it would be easy to convert the 100 launcher to shoot blanks by just blocking the bullet tube in front of the muzzle of the rifle with a thin metal or cardboard disk so all the force of the blank is diverted up into the cup. I think that should work.
Here's the post where I made blanks to shoot in the Lee Enfield rifle's Cup grenade launcher. Need help in making grenade launching cartridges? I used a combination of smokeless and black powder to shoot tennis balls out of the launcher. This is the mix that the real blanks used also. I don't see why it wouldn't work with the 100 launcher. Can't see anyway it could hurt the rifle or launcher, Ray