When the assault on the Second Amendment reaches a tipping point, and I believe it will eventually, I wonder if a Governor of a state with a patriotic majority might formally declare a well regulated militia consisting of all vote eligible citizens with clean backgrounds. Restrictions on firearm ownership would seem to be moot in that case. Just musing...
The 922(o) ban on full-auto guns has an interesting exemption applicable to your scenario. The Left would be apoplectic if the end-run around their “semiautomatic assault weapon ban” (very carefully worded) let every Selective Service registrant (or whatever category specified) with a clean record buy new select-fire M4s at fair market value (about $1000). Go look up 922(o), exemption (2).