On Wed, Jan 14, 2015 at 07:36:28PM -0500, Richard Aiken wrote:
> IIRC, it's a King-Kong-sized autorifle (I always imagined something like
> what Warhammer 40K miniatures are shown to carry) that uses antimatter as
> it's "gunpowder."

Here I thought designing chemically propelled guns to withstand
chamber pressure was hard enough.  Let alone the fact that at those
energies, the so-called "projectile" may as well be made of dust,
except that it will hold together even less well than that.

My calculations were based on the idea that the projectile was
accelerated intact by some magical force.  If it's using thermal
energy (constrained by magical means), it's a lot simpler: the effect
will be that of an exajoule explosion occurring within less than a
hundred metres of the muzzle, as the cone-shaped blast of plasma dumps
its energy into the air.

- Tim