D&D 5E (2014) Let's Talk About Guns in 5E

[W'rkncacnter]

One of the things I really liked was when 3e tried to expand alchemy into other areas. The PHB had alchemist fire, acid, tanglefoot bags, etc. Eberron added alchemist frost and alchemist spark (doing other elemental damage). The problem is that alchemy doesn't scale and quickly becomes obsolete to magic, but the idea would be interesting if they could somehow fix the scaling issue...

tie dcs to an ability modifier, make them simple weapons instead of improvised, and let them be deployed in place of an attack. that seems like problem solved to me.

 

[LuisCarlos17f]

If the industrial revolution had started in D&D multiverse the main factories would be in the plane of mechanus. The handicap would be the transport of products toward far zones.

Another possibility is that this technology has already been discovered but is relatively prohibitive due to patent fees, and the spellcasting guilds have gone to great lengths to ensure that this remains the case.
And we don't talk only about firearms but also giant crossbows shooting explosive arrows in the bastlefield.

Firearm malfunction - Wikipedia

en.wikipedia.org

If magic could cause "squib loads" in enemy machine guns then can say goodbye to these.

Maybe there are magic zones with a "watering gunpowder" effect. The ritual to casting this could be really slow but if it in the building of a stronghold then the inversion is worth. The war deities could gift magic banners that cursed all the firearms in the nearest area.