STT-15 Ambi PILLAR Billet Lower Receiver

Our STT-15 lower receiver was born out of necessity and a desire to have a true ambidextrous AR-15 M4 platform. Allowing it to accommodate all shooters without the need to add countless costly add-ons. Whether you are a right- or left-handed shooter, or forced to shoot with your off hand, the STT-15 has you covered! STT-15 is designed specifically for situations in which there’s no room for error and you must use your rifle to take that shot!



The STT-15 was born out of a desire to develop a true ambidextrous AR-15 pattern weapon system, built to the tightest possible tolerances. The full suite of ambidextrous controls comes standard on all Pillar AMBI receiver sets and lowers, and allows for standard manual of arms from both the right- and left-handed operation of the weapon.    

We machine the STT-15 directly from a billet of 7075-T651 aerospace grade American aluminum on our brand-new Haas CNC machinery. This allows us to hold ultra-tight tolerances and make sure that the final product is exactly as designed, and weigh in at only 1 Lbs.3.4oz. The finished receiver is then finished in Mil-Spec, MIL-A-8625 Type III hard anodizing, or our robust ceracoat options by HRH Custom Coatings. 

Our philosophy with everything we do is simple. It has to work. Every time. The STT-15 is proof that you don’t have to sacrifice form to gain function. Our workhorse receivers are built from the ground up for reliable hard use functionality, and they look good doing It too.  


  • Huge 1.38″ Integrally Machined Magazine Well Flare
  • Ambidextrous Quick Attach Detach Sling Swivel Points with Anti-Rotation Stops Every 45 Degrees
  • Ambidextrous Bolt Release
  • Ambidextrous Magazine Release
  • Bullet Pictogram Safety Selector Markings
  • Set Screw Trigger Creep Adjustment
  • Set Screw Upper Take Down Tension Adjustment
  • Shooter Ready Finger Rest
  • Oversized Winter Trigger Guard Perfect for Gloved Hands
  • Dowel Screw Assembly
  • Ultra-Grip Texture on All Controls
  • Backed by STT’s Unmatched Lifetime Warranty
  • Made in the USA



Santan Tactical
Direct: 480-726-8261
Fax: 480-393-4018
Mailing Address:
2223 West Pecos Road
Suite #6
Chandler, AZ 85224