Think about 6 times, last time about 20 years ago if not longer, and no they didn't use three crates of dynamite, I mean don't go for the kill go for OVERKILL!
Also, a pretty good way to off someone is to back him over with a dump truck.. less kboom.. hmm.. potentially more squish though..
the dump truck does provide a handy way to remove the remains, and it is mobile.
all well and good but we require energy based personal defense and/or doomsday weapons.
Now if we could power up the plasma rifle to make it shoot a much smaller pellet, almost infinately dense perhaps of a 2 dimensional carbon material, perhaps we can get the collision of the micro-dot with bone to form microscopic extremely short-lived black holes.
The black holes themselves would cause very little bone damage but microsecond bursts of Hawking radiation would destroy the molecular bounds of surrounding tissue and with luck would leave the human body a pile of spare parts and goo. The advantage is that this weapon would be difficult to shield from, but the disadvantage is that it might require bursts of shots to get the projectile to have a successful collision. This, along with the irrational fear of black holes, the irresponsibility of the system, and the whole concept of bits of the victim being spaghettified beyond the event horizon until the end of the universe or something makes this weaponry highly Evil. 7.5 out of 10 on the Blofeld Scale.
But I do hope you will use your Jaws knowledge to come up with some sort of practical Shark based defense system.
hmm.. combine BOTH weapons into one big ass shotgun and tadaa.. good idea? 
