When is Battery a Misdemeanor

My question involves criminal law for the state of: Maryland
In 1979, I was found guilty of 1313/M battery with a 150 fine. Can anyone tell me is this was a felony or a mistermener. Reason I asking is I have always been able to buy a gun's in md now 35 years later with the md new gun law's there taking my 2nd amendment right away. They made me turn in all my gun's

The M probably indicates misdemeanor. Assault is usually a misdemeanor in MD unless it's directed against a law enforcement officer.

Was the battery against a spouse or intimate partner?