Does anyone know if its a go or no go and how one could find out for sure?

I have a friend in who is temporarily living in Bridgeton/St. Ann now, just bought 15 acres in Washington County (Blackwell MO) and has a decent amount of woods/Pasture.  Pretty big Gun Guy, He'd fit in good here.  He is asking me and I'm thinking it is, but not 100% sure.
 

I asked at my Town Clerk's Office .

They looked at me like I was stupid, but I got the answer I wanted.

I told him he should call the Sheriff's office on a non emergency line and ask.

If they say it's a no go, ask them for a copy of specific ordinances...

Here is another to look at:

RSMO 537.294

I agree the local sheriff would have the most insight.

It seems long as you are shooting in a responsible manner (proper backstop, etc), not violating the unlawful use of a weapon statute, aren't a convicted felon, and on private property not subject to ordinances in place by a city or a county, it is legal.

I've never seen a Missouri law that stated a minimum number of acres to have a range.

Another source could be the Department of Conservation if you run across one of them before getting to the Sheriff.

There are no county codes in Washington County which regulate shooting on your own land.  I guarantee that if you spend a couple days on the land you will hear gunfire from the neighbors.

I live in a more populous county and have shot my guns and machine guns on my peronal range for over twenty years with no problems.