Projectile weapon firing 8mm projectile containing one gram of matter and one gram of antimatter, rather like a tiny photon torpedo.
What kind of range on that? I don't think I'd want to be too close.
The personal force field is a good idea and would lend a bit more credibility to the (budget-dictated) small arms combat Trek ground wars appear to consist of. On the other hand, the apparent diminished effectiveness of hand-held beam weaponry in DS9 (non-fatal burns and disruption as opposed to TOS/TNG style glowy disintegration) suggests that at least some kind of armor is being utilized in SF uniforms. (But ironically not Breen power suits.)