Haha I'm surprised this thread is not locked yet
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The below is stated precluding special misdemeanors, ie domestic violence is treated like something different all together that prevents firearms ownership for life federally.
One thing to point out, the federal government does not really recognize the term "felony" in the same manner states do, who can all recognize the term differently, the metric used to preclude firearms ownership (or possession, or whatever you want to call it, not gonna debate that) is convicted of a crime carrying a sentence of > 2 years.
Now, some states a felony might not carry that for certain felonies, other states a misdemeanor might carry > 2 years. Soooo a convicted felon by state law very well might be able to own guns by federal measure and someone with a misdemeanor conviction might not.
States have piles of their own laws and without looking at the state you can't make any generalization. Some states preclude firearms ownership for life upon any minor drug conviction - and a NICS check will result in deny if the agent has their head screwed on right as they do checks with respect to state laws... Other states have the potential to restore firearms ownership for what would normally be considered a serious felony carrying a life sentence even, and the federal government is supposed to uphold those rights restorations provided the restorations restore the subjects right to hold public office and participate in jury duty (that is how the feds measure an expungement/annulment/sealing/whatever-the-state-calls-it feature of forgiveness for a crime - rights fully restored mean you can own guns by the state law plus are not barred from all other such potential civic duties).. If rights are restored legally that does not mean a NICS check will not deny them incorrectly, which is a problem w/ NICS.
Now states can have laws that violate fed laws, for instance in NH they say if you were convicted of a felony in another state that NH does not consider a felony, you are not barred from firearms ownership - so the state cannot use their laws to prosecute someone in that situations, but that does not mean the feds couldn't or that the person will pass a NICS check.
The feds do have laws on the books also to restore rights to people barred by crimes, but as has been stated, are not taking those applications for relief.
Personally I think the whole thing is a bit over-reaching. If someone goes 10-15 years passed the end of a sentence clean I think no matter what, they ought to be able to own guns again, I don't care if they murdered someone with a gun, people are often different people after that much time and really violent people are gonna get in trouble or get a gun if they want it anyway. Many states use the features of this federal law just to cut down on gun ownership, ie state of MA has made a first time DWI a 2.5 year sentence, with no relief possible for life, even though nobody has even done such time for the crime, as well as a slew of other crimes that shouldn't bar firearms ownership at all if you ask me.