How do I find out if theres a gun registered in my name?

I didn't think you had to register a rifle?

Call the State Troopers Barracks in your state and they can look it up in the federal data base.

Another very useful piece of information I didn't know I needed to know.  This is why I'm so addicted to BYC.
cool.

Do you still have the serial numbers and the type and model of the rifle ?

If so, you can WRITE the ATF federal administration and formally request a history of your rifle since you did have it registered in your name at one point.

EVERYONE. Reatain the serial numbers, make and model of the guns you own and have sold off. Times are looking strange.

Im always glad to find a use for any of the crazy info that takes up space in my brain.

DH always laughs at the things that I know but I cant remember to pick up milk on the way home or shut off the oven when I am done making dinner.

Its nice to be loved on BYC for my useless info... 

Most states do not register long guns but I am not familiar with MN laws.  Having said that when you purchase a rifle from a dealer you fill out form 4473 see info here: http://en.wikipedia.org/wiki/Form_4473

This form goes to the ATF and I suppose if this gun were used in a crime the person who's name is on the 4473 is likely the first person they would contact.  Most states do not require the transfer of a long gun to go through a dealer so after that first transaction there may or may not be a record of later sales.

Gun laws very greatly state to state so you definitely don't want to be taking advice from people on the internet go to your state website and see what you can dig up.

A couple of (or more) thoughts:

1)  You mentioned "ex".  If the "ex" was a husband, then all is good.  If the "ex" was not a husband and you bought a weapon for him knowing he had "a past", then the BATFE calls that a straw purchase.  That is bad as it is a federal felony.  Right now, BATFE is going after straw purchases, especially in the southwest states, as they are under pressure about weapons in Mexico.

2)  If the rifle was sold to a pawn shop, it should have been entered in the pawn shop's FFL bound book.  If that happened, all is well as there is a federal document showing the rifle is no longer in your possession.  If not, a receipt showing the sale to a pawn shop would be a big help.  If the pawn shop did not enter the rifle into the bound book, the pawn shop committed a federal felony.  If you sold it or pawned to a pawn shop, the rifle should not be in your name, and there should be no issues.

3)  Depending upon your state of residence, a rifle purchase may or may not be registered.  [eta]  MN does not register long guns.[/eta].  If it was registered, there would be state paperwork as well as the federal form.  Most states do not require the registration of rifles.  Thus, the only way to track purchases would be through BATFE Form 4473.  That is the form one completes when a firearm is purchased or claimed from pawn.  BATFE only gets those forms in one of two ways: 1)  an Federal Firearms License (FFL) holder that surrenders the license must mail the forms to the BATFE.  2)  The weapon becomes of law enforcement interest and is traced by following the paperwork trail on Form 4473.

If the answer to 1) is not an "ex-husband", this could be bad.  So do not answer that question online.   But the rifle was disposed of in a pawn shop, so that is very good.  While there are FFLs that break the law, they are few and far between. 

My advice: let it lie.  Most rifles are never used in crimes, regardless of Hollywood.  Most rifles are never registered by states.  You sold it to a pawn shop.  All in all, this rifle is in someone's legal possession.