Re: possible reason we never seen the phaser rifle after w.n.m.h.g.b.
I just figured they never really ran into anything that couldn't have been handled with a regular phaser pistol so they never needed to use the rifle again.
The landing party could have used it against the parasites on Deneva. Phasers 1 and 2 barely stunned the creatures, so one can imagine how a Phaser rifle would have handled the creatures.
"...to be like God, you have the power to make the world anything you want it to be."