This is an opportunity for Red States.
1. Offer to fund Blue State gun confiscation/buyback with stipulation that guns are shipped to Red State for decommissioning.
2. Remove firing pins from guns, sell the now non-functioning weapon to Red State citizens as a conversation piece, modern art, etc. Sell the firing pin separately as a toothpick, scribe, etc. Plead ignorance when it becomes apparent that the people have reassemble the weapons.
3. Having disarmed Blue States, tell FedGov to take a hike on pretty much everything.