Are there any books out there about a time-travelling Egyptian Pharaoh armed with a glock who is trying to kill baby Moses?

I do enjoy a challenge.

There's a time-travelling Sphinx in All-Star Superman (by Grant Morrison) who threatens the eponymous protagonist.

Superman, as many know, is an excellent allegory for Moses - he is effectively found as a baby in the reeds, gifted with a special purpose and abilities. The Sphinx, of course, represents the Pharoah.

Sadly, the Sphinx doesn't have a glock, so it's not exactly what you're after.