If you happen to be bored, have a little cash and a lot of ammo to surreptitiously waste, I have a great suggestion. I ordered a hiperfire 24C trigger (without a doubt the best AR trigger I have ever had the pleasure to shoot) and had, coincidentally, a knock off bump fire stock. Well, somehow they decided to merge and become something far greater than their parts. For about $300 you cats can have a very fast firing AR legally. And I mean crazy fast. We were getting approx 600 rpm on review of the videos - d4rn near FA but without the $20K and paperwork. It made that useless bump fire stock go from the bottom of my heap to the very very top. Instead of a lackluster stock with humongous learning curve, it became a first try 2.5 sec mag dump. Try it out, I havent been that happy in months.