At Sons of Liberty Gun Works they believe in Quality Mil-Spec or better parts. They believe there is no substitute for quality and that your gun should be built right the first time, ready for hard use right out of the box. They believe a quality Bolt Carrier Group and a quality, accurate and long lasting barrel are the heart of a Combat Grade weapon. They believe in properly tuned weapons using the correct gas system length and quality buffer system components. They believe in their products and back them up with a Lifetime Warranty.