This Might Seem a Bit Extreme At First

Convicted felons may not possess firearms or ammunition--even a single round. The theory is that if you find a convicted felon with ammunition, he's probably not in possession of it for old times sake, or as a good luck charm, but as evidence that he has been in possession of a firearm recently, and is too careless to do a proper search of himself for ammo. From the September 21, 2007 Idaho Statesman:

A former Northside street gang member was sentenced Thursday in federal court to 32 months in prison for being a convicted felon in possession of a single .45 caliber round of ammunition.

...

After he completes his prison term, Mendoza will be on supervised release for three years, during which he may have no contact with any gang member or gang paraphernalia.

Mendoza was arrested after officers located one round of ammunition in his front pants pocket. He had previously been convicted of grand theft and possession of a controlled substance in Canyon County. Under federal law, it is illegal for a convicted felon to possess either a firearm or ammunition. This was Mendoza’s 13th adult criminal conviction.

This being Idaho, the first comment was complaining about the light sentence!

I have a few misgivings about the failure of federal law to distinguish between violent felonies and federal felonies such as turning back a car odometer, but Mendoza doesn't sound like someone who deserves much sympathy.