He's extremely dumb to have his intent to deceive the federal government written down. There's apparently text messages between him and others where they openly talk about how using the police sales method of importation is just a front for being able to import and sell shit they like.
Really sucks that he's going down for it, but still an absolute retard for having this shit written down.
They imported AK-12s (from Russia) against the sanctions, with the exemption that the rifles were intended to be used for marketing and selling to police departments. The texts they had with each other planning everything showed that was just bullshit and they just wanted AK-12s. I'm pretty sure that is the "Conspiring to violate sanctions" portion.
A similar thing that might be understandable is California cops buying guns civilians can't have and selling them to civilians for a hefty mark-up. They are supposed to be buying the firearms for themselves, not with the intent to re-sell them. I think there was a case earlier this year where some cops got busted for something similar, texting each other their intent to buy and re-sell the firearms.