Is that fantasy or scientific fiction, fan fi or sci fi ?
How much energy does that xeelee handgun have, to check if it can fit inside a handgun (i don't know what mass scattering means)
Just as reference if you focus a stellar Archimedes weapon to a point in space for about an hour it will create a blackhole with a Schwarzschild Radius of about 0.23mm*10e-9. If the gun has too much energy its S.R. could be larger than the gun and collapse into a blackhole.
700 million light years from us is a possible space civilization that spans 1000s of galaxies https://steemit.com/science/@towjam/bootes-void
Would that be big enough to outgun everything in sci fi ?