what are the consequences of being in possesion of a fire arm with one prior on record
It depends on what your prior is. If you have previously been convicted of a felony, you are never supposed to have a firearm in your possession at all. If you have been previously convicted of a various class of misdemeanors, you are prohibited from having a firearm for 10 years from your misdemeanor conviction. You are going to have to provide more detail, such as the prior conviction, including statute, and dates.
If you are a 'prohibited person', barred from owning or possessing a firearm [and ammo], because of a felony conviction, or a court sentencing order, then such possession is both a federal and state felony, with serious prison time. If you are charged with that crime, get an attorney. If serious about doing so, feel free to contact me.