San Tan Tactical STT-PILLAR-1 STTPILLAR1: With the various styles of today’s shooters, everyone wants to run 15” & 16” long rails and grip the rail as far out as possible to gain the most control of the rifle. That’s like attaching a 16” lever to the rifle. The truss design acts similar to a bridge that carries and distributes the stress across the entire platform versus putting all of the pressure on the material right behind the threads of the receiver. The extra strength gained from this design is not only to help the receiver. It also, in turn, helps improve your accuracy. When most people think of a billet receiver, they think of a blocky, heavy, thick design that is CNC machined. San Tan wanted to break that mold too. Thru the use of 3D CAD modeling software, they were able to save weight in places that extra material didn’t have a purpose, such as the forward assist block and the shell deflector. Typically on billet uppers, those are left bulky due to the difficulty of removing material on all of those angles. After all of was said and done, the new STT receiver came in at only 8.2 ounces. That’s lighter than some slick side uppers.