Civilian Arms Training Source provides tactical firearms instruction for shooters of varied abilities and backgrounds, with an emphasis on safety, practical skills, and preparedness. Based in La Palma, California, the organization serves civilians, military personnel, and law enforcement through training centered on Center Axis Training Systems (CATS), an evolved approach rooted in the original Center Axis Relock method developed by Paul Castle.

Its classes teach a dynamic, adaptive style of gunfighting intended for close-quarters encounters and other high-threat situations. Training focuses on awareness and control across a 360-degree environment, weapon retention, tactical movement, and pistol proficiency, with applications that can extend to rifles and shotguns. The organization also describes its method as accessible to people with certain physical limitations.

Civilian Arms Training Source says its instructors were trained, certified, and mentored by Castle before his death in 2011, and that they continue to refine and teach the system. Prospective students can review classes and schedules and book sessions.