I would check with my insurance company first. Seems like something that could change what kind of / how much insurance you need. Just guessing, this post is not legal advice.
And I would stick with reputable ammo from 1st tier military nations.
You can sell all you want, just be sure to get the caliber right. A local 'flea market' dealer here in Skagit County likes to call Bulgarian 7.62x54R in clips 'WWI 8mm' for $8 a pop. He tries to be a crook, and it doesn't sell. If he sold it as Bulgarian 7.62 at $3 or $4 a clip, he'd make money.