I will be wrong on this, but I'm going to say with 90% confidence that Galarian Slowbro is meant to wield a sword, not a gun. A "shell" is the hand guard of a sword, "quick draw" makes perfect sense for drawing a sword from its shell, and the games are Sword and Shield.
Also matches "armor" better than a gun, and we all know Slowking is going to have something to do with a "crown," so... I mean, why do you think they picked these two to be their promotional duo?
For that matter, the one glimpse we had of its design suggests inspiration from a noble of some kind with a cravat, and I think drawing from something like swordfighting in a style that's supposed to be elegant and formal (like... I dunno, fencing?
help me I don't know enough about swords) would make sense enough to follow through on that - more so than something obviously violent like a gun.
We have other Pokémon that draw inspiration from firearms, if usually stylized cannons and such rather than straight-up wielding guns I say in the Generation that gave us Inteleon... but even that's just a joke on finger guns, but for some reason I'm having a hard time picturing Slowbro joining their ranks.
(I'm guessing it's gonna be something silly like... Slowpoke fishes up a Shellder with a Galarica Twig, and then the Shellder evolves around the twig instead of its tail and becomes the shell of a sword.)
Since none of this is at all interesting except Quick Draw, what do you guys think that'll do? Based on Galarian Slowpoke's flavor text, as
Whitephoenixace shared, I'm wondering if Slowbro is going to be super slow most of the time as always but gets circumstantial priority on some of its moves (like it has priority on its first turn in battle, or it goes first once "in a pinch" like the Custap Berry) - the former in particular would be an interesting gimmick for speed control and revenging sweepers.
It could also be the opposite - something that triggers only when it
does go first, like the Fossil moves - and if it is indeed sword-related, I'm betting that it'd be a (boosted rate? guarantee?) for a critical hit when it strikes first... Or just inverse Analytic.
"Has priority on its first turn and then is super slow" is probably my favorite of these guesses, though.