how do I find out if a gun,shotgun rifle, has been stolen, I dont want to get the cops in on this?
Why on earth would the cops be in on it? You have way too vivid of an imagination or else you watch TV too much.
As long as you are buying the firearm from someone you believe to be the bona fide owner of the property, you are covered.
If you like, insist on a Bill of Sale. Any criminal seller of firearms will balk at this measure, whereas most legitimate sellers will want a copy of the transaction as well.
Punt gun (shotgun) video – best angle