Hey there, thanks for the feedback! Always appreciate to hear from a fellow modder.
The pistol and shotgun can be fired super quickly by tapping the Fire button. As for the SSG, it did go through a few design iterations as I didn't want it to simply be a rapid-fire upgrade to the shotgun, I can see how the need to pause after firing twice can feel a bit clunky. I might give it a rework.
Glad to hear you found the mod fun! I wasn't sure if folks would take a liking to it since high-power mods like Russian Overkill, Trailblazer and Doom Incarnate already exist, but perhaps I was being too modest, heh