So for firearms, go to your local blacksmith and he’ll make you an Eli Whitney muzzle loader?
Was that supposed to be funny? The only thing that was funny, was that you thought it was funny.
But since you brought up firearms, ARMSLIST.COM is a great place to look up locals who are selling their firearms.
https://www.armslist.com/inside
Select your state, and then drill down to the local city level from the drop down box on the right.