I installed way to many of these devices in the late 80's and early 90's for people in Texas who bought them for their semi auto rifles. While I was able to get them to work fairly reliably. Acccuracy seemed pretty poor.IMHO It did empty a 30 round AR15 mag quickly when it worked.Sorry, I guess I should have had this link in my original post.the only thing i can find for "tac trigger system" is spring loaded bump firing trigger assists, which are all junk. can you please refer us to what you are talking about?
SW
http://www.gungarage.com/rapidfire.htm
The video for it is #4. Seems pretty cool.
Having said that. I agree with SW that they are junk. I spent way to must time readjusting them for people who bought them.
But feel free to buy one and reach your own conclusions.
Walt