It will be still based on distance. Othervise it can be problematic and less dangerous.
I made this a few weeks ago as an acid gun test:
http://www.youtube.com/watch?v=ZcOKUD-I6Ww&list=UUgeotTTb4AW_l2w8cNPRssA&index=4&feature=plcpIt works as following:
-Flame textures swapped for basigas since it looks good enough
-Flamer muzzle particle system edited so it falls to gravity [in the video i hadn't made it yet]
-Flamer trail particle comes from the flamer missiles in random direction + a bit of inertia from the missile
-missiles fall to gravity and bounce half
TODO: -Make it explode upon first contact and create 'mini' flamer missiles in all directions [ quake 3 clusterGrenade code]
With the acid tube, you could do something similar.
But i agree with you, in some circumstances it will be less dangerous.