The Eggnogstic wrote:
. . . A pistol grip with a chamber that rests across the wrist is the most practical design for a human held hand weapon.
For an explosive-propelled projectile weapon, yes. But an energy beam weapon could have a completely different shape.
It's not about the inner workings of the device that I mentioned this. It's due to the hand-eye coordination needed to aim the device. A TOS P-II phaser is fine for close quarters but not long range. Anything further than 50 feet needs direct eye sighting to be effective for precision shots.
The Space:1999 hand gun actually makes a weird squiggly vertical laser pattern, so all you need to worry about is one axis (X). With that you can kind of get away with the staple gun design.