@ snoox: About the US Rifle grenade, look at this film
http://www.youtube.com/watch?v=vukYdgepSZkAbout the German rifle grenade. I would not know. I think it will only be full force so one hell of a kick. There might be a valve on the side to release some pressure so you can adjust the range that way (and kick) but i have seen them from very close by and did not see anything.
I wanted to buy the riflegrenade kit for my mauser, but those things go from €700 to €900 so it will take a while before i ever buy one.
If you give me the cash i will even make you a nice film and a 2 page long text of how it is
I will even buy different German riflegrenades to test it with.
My father shot riflegrenades in the army, and so did my grandfather, maybe one of them did it with a mauser, will ask next time i see them and post it here if they did.
@ flyboy: If you just put the grenade on the end and shoot your grenade will definatly fail and very likely explode in your face. You are not sepose to shoot true them, i have see an original box of German rifle grenades once and the blank bullet that you have to use is taped on the grenadae itself.
And i think another tread on this forum came to the conclusion that the faust is a recoilless gun.