Sorry I haven't given any sort of feedback in a while. :/
I haven't tested the latest updates much, however, from what I've seen so far:
Sarah: I suggest lowering the fire-rate. Right now it seems equal to ROF the heavy pistol. Though it really depends on exactly what kind of gun you want it to be.
Pop-Gun: Seems to be really balanced, ROF, damage, spread, etc. So far this may be my favorite shotgun. I get a bug when it has no ammo left: the weapon continuously tries to reload. (I don't think this breaks anything, just gets annoying)
APG: Seems really balanced, like the normal Pop-Gun, but in a different flavor. This weapon doesn't seem to have the reloading glitch.
Motor-Mouth: The wind-up sound are good, though it spin-down sound should match the animation. (just me being picky though ;)
And that's it for now. As always, really great work so far!