Originally Posted By GearHead_1:
I believe what you are describing is similar to a Hell Fire device. My understanding is that these are legal because in short there is one round fired for each pull of the trigger even though it isn't a typical pull. I've seen these in action and they are complete junk. I know that there is a mystique about having a full auto rifle but I think you'll find a number of owners tell you that it isn't what it is cracked up to be. I've talked with many that fall into this category. That said, do it right or don't bother.
This. I owned a legal M16A1 for 24 years and I think I had it out to shoot it maybe 10-15 times max in all that time/