It seems like everyone and their mom makes a piston-driven AR-15 these days. And with good reason.
Piston-driven guns run cleaner and cooler than a standard direct impingement (DI) system, making them a big draw for high volume shooters such as those who shoot competitively like in 3-Gun.
They also just make all around great guns if you want to get into AR-15’s a bit more and try something different.
Who knows? You might just fall in love.
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source: https://www.pewpewtactical.com/best-ar-15-piston-uppers-conversion-kits/