I was thinking the same thing. There are definitely restrictions on the size/function of guns, and you have to fill out paperwork, get fingerprinted, etc to get past those restrictions.
To buy any gun at a store, you also have to have a background check, which you generally don’t have to do for knives.
For gaming, I’d suggest https://mstdn.games. Not entirely sure if NSFW is allowed, but I’ve never come across it, personally.