I took a browning b78 and put a 35 caliber barrel on it chambered to 35 whelen AI. It is a killer with a 225 grain accubond. It qualifies as a primitive gun in Louisiana.

I have to laugh at the definitions of many states.  Missouri is no different.

I think that it's safe to assume that a lot of these regulations are written by people that know nothing about shooting or cartridges in general. Here in crazy old N.Y. the cartridge regulations are surprisingly liberal and allow you to use anything other than a rimfire. For most of my life shotguns with slugs and muzzleloaders  were the only thing that you could use in the county where I live because the feeling was that rifles would increase the chances of little Johnny across the valley getting shot by some long range rifle. The opposite has happened however and since rifles have been allowed the number of shooting accidents has decreased considerably. I cringe when I see some guy using a 300 Mag for a 125 lb. deer or when I see the black rifles being used but I think that rifle use leads to fewer deer being wounded and lost and that's a good thing.