Should I allow guns in my D&D Campaign?

(Not a Blunderbuss.)
I’ve seen a lot of takes on this particular subject over the last thirty years or so. It’s actually a debate that’s been going on since 1st Ed AD&D Dungeon Master’s guide introduced it. There are numerous articles written about the subject and countless opinions. It seems like anyone who DMs the game has their own take.
And that’s a good thing! At the end of the debate, the best answer on this subject is that it is up to the individual DM and group to decide if they want to allow gunpowder into the campaign or pretend that it was never invented. Then the next debate is the tech level of said firearms. Matchlock, Flintlock, cap and ball, or more modern?
The Blunderbuss was a big deal in 2nd Ed.

One of my players back in the day insisted on putting one on practically every character. Why? Well, look at the damage. Okay, big numbers unless the thing randomly explodes in the firer’s face. And then there’s that pesky reload time.
Not everyone min/maxes the same way. A light crossbow iirc could put three or four times the number of bolts downrange more accurately and without a chance of critical oops in the same amount of time as it took to reload the Blunderbuss.
Then came the notion of black powder bombs and grenades being lobbed about. Healers were getting overworked. Druids were becoming scarce. The mages were just standing around saying, “You know I could throw a fireball for way more damage…”
But then again, doesn’t black powder sort of negate the need to spend years studying magic if a common peasant can shoot anyone with one of these man-portable cannons or lob a bomb in the general direction of something and destroy it? The dynamics of fantasy medieval warfare change dramatically with the introduction of firearms of any kind.
Desperately trying to keep the fantasy in the game.

I’ve said for many years that fantasy game designers don’t know how to write a modern RPG that involves guns. It’s so much easier for Mr Potter to point his wand at the target and yell “Allakazotimus!” to fire off a lightning bolt. It’s going to be unpleasant for a knight in full plate to get hit with said electricity, to be sure, but it’s easier to write in terms of rules.
This is in comparison to firing a Viking 9mm SMG with a 30 round mag on full auto at a target 14 yards away wearing Kevlar body armor. What’s the grouping? How many rounds are expended? Did it jam? Firearms combat involves some degree of real world data and knowledge of statistics. Who wants to go to all of that extra effort?
I’m trying to leave real world opinions and politics around firearms out of this discussion because I think a LOT of people in the world have had enough bad experiences with firearms, explosives and so forth. I grew up around hunting rifles and shotguns, and I have studied firearms extensively because of my interest in roleplaying games. Again, not everyone cares for anything involving real world violence. Honestly, can’t say I blame them.
Many of us indulge in fantasy roleplaying to escape the trappings and tribulations of the modern world. It’s fun to play a dual sword wielding elf ranger or a half orc barbarian with a great club. Yay magic and dragons! Why spoil it with things that remind us of sh*t that happens in real life?
It comes down to Session Zero.
Uh oh. I said what some think is a dirty phrase in the RPG community. You either love it or hate it. DMs/GMs sitting down with their players before the campaign starts to discuss expectations and boundaries in the game. Personally, I’ll red flag any kind of guns or gunpowder in any fantasy setting where firearms aren’t already well established.
Why? Because I know people are pretty sensitive to gun violence. My son’s school just had a drive-by shooting that ended in a fatality and two critically injured a couple of weeks ago. My oldest son is pretty freaked out about it. So, we’re keeping my game very swords and sorcery.
I have another campaign, not D&D, that involves swords and pistols. It also has magically powered mecha and steampunk/magic tech. It’s not even the first setting I’ve made like this. Yeah, fantasy with guns can be a thing if everyone’s cool. But not in Forgotten Realms or even my regular D&D world. If the expectation isn’t there, don’t roll with it.
Thanks for stopping in. Have a marvelous day! I appreciate you.