Piston guns can be very accurate if its done right. The scar17 m1a and m1 garand is proof of that. But your not going to get there by a add on kit . It has to be done as part of the overall design process.
The ruger ar15 is something that came from a very vocal minority in the gun forums speaking on a topic they have no real experience with. Ruger saw that as an area of demand rather than the fad internet jockey nonsense it is. So they went pricey piston trying to solve something that has never been a problem in the modern ar15 system.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent