Smyth Busters: Are Piston-Operated AR-15s Better?
This guide breaks down the fundamental differences between piston-operated and Direct Impingement (DI) AR-15 systems, as explained by Brownells technical experts. It covers how each system operates, their respective advantages and disadvantages regarding cleanliness, temperature, weight, and cost, and addresses potential issues like bolt tilt in conversion kits versus dedicated systems. The conclusion favors DI for most users due to its refinement, reliability, and cost-effectiveness.












