>>513012982
We have three categories.

1: Weapons that require no licensing, registration or exemption.
2: Weapons that require an exemption
3: Weapons that require licensing, registration and reasoning

For category 1 the best you’ll get is a bow or a knife. A single shot pistol is exempt from regulation if it was manufactured before 1900, and a longarm manufactured before 1900 is exempt if the ammunition is not commercially available. These would include flint locks, cap locks and so on, but can be incredibly difficult to find and if you do find them they’re usually very expensive. They are however technically the “best” weapons you can get in Cat 1.
For category 2 you are looking at repeating mag fed crossbows, swords and so on. Category 3 is modern firearms.