Originally Posted by Brian McIlmoyle
The issue with these things is that to make it light enough to be safe.. it won't fly..
sure once all the propellant ( water ) is expelled I expect it is quite light...
but what about the bonehead who walks in front of the tube just as you drop the bomb and takes half a kilo of plastic and water in the face at launch velocity?
I abandoned my own mortar project for exactly this reason. US military doctrine for dropping a motor down a tube is to follow through downwards such that the loaders head is below the barrel end and thus well out of the way of the launched round. After firing early proof of concepts, I found myself wanting to drop the round and keep my eyes up downrange to see where the round landed. This puts the loaders head above the barrel end and potentially in the way of the projectile if something unexpected happens like a loss of balance. I never got hurt, but I just couldn't see the general public deploying an effective mortar safely. We don't have the discipline.
An emplacement also needs strict area control to assure that other players don't walk past the firing axis. Obstructions like a sandbag ring could prevent the uninitiated from walking past the barrel during firing, but this kind of site building is not typical in most airsoft skirms. Mortar crews must be well trained for them to be safe.
All these safety issues coupled with the need for the round to be light (so as to be safe downrange) makes it difficult to make something with a significant effect at the impact site. That and you have to be willing to lose the round too.