This is a simple idea, in which the shield gun's impact attack is modified to operate at range as well. Instead of dealing any significant damage, however, its primary purpose is to impart kinetic energy to the target – that is, knock it flying. (Think of the gun used in Minority Report.)
The weapon is of little use by itself; however, it could be handy to knock opponents off high walkways; or away from pickups/flags/control points; or into lava/fans/lasers/etc. If you were really tricky, you could use it on teammates for assisted jumps.
The real purpose behind this mod is for use in conjunction with the ragdoll-on-impact mod discussed in Karma Ragdoll. Hit an opponent with the kinetic rifle, and send him tumbling through the air; switch to a more lethal weapon to finish the job. (That, and it would be pretty funny to shove people down hills on terrain maps. )
Kagato: This seems like a pretty basic weapon mod, so I intend to use it as a learning exercise. Don't let that stop anyone else, of course
RDGDanClark: That sounds like fun, you should definitely post your progress. I would suggest giving the shield gun (SG) a beam fire akin to the beam fire of the shock rifle. Once you do that, all you need to do to the SG is change the damage to zero and the momentum to something huge. If you check out the [3D Buzz Video Tutorials], the simple mutator they do modifies the shock rifle into a concussion rifle – by altering the momentum like we're talking about here. If you'd like some pointers in the right direction, post a request here or you can contact me via email (listed on my RDGDanClark personal page).
GRAF1K: I had the exact same idea. Ask MeanFish if you don't believe me.