The vague language in our gun laws make this a touchy subject, and I wouldn't do what I'm about to suggest without researching it a little. But I believe the lower reciever is what counts as the illegal rifle in this case. You could bring the stripped lower to one of the many amnesty gun buybacks that have been popping up in the state and maybe get a some money for that. Then sell the rest of the rifle as parts online. The touchy part would be the upper with the bayonet lug. Whether or not that, in itself is illegal without the lower would be a question worth looking into.
There are many things in life that are out of my control. Recoil isn't one of them.