What Blade describes above is the problem with most buffer/double spring systems. The Sprinco overcomes this and works great. Sometimes they require a bit of tuning to work right but its minor. It will not work right with puff loads as it is designed for full power stuff. If you were to have a problem with it call them, their customer service is fantastic and on par with Dillon.
Matt's Custom Glock Resource - Because Stock Sucks!