Greg “Sully” Sullivan is a veteran law-enforcement professional, firearms instructor, weapons armorer, rifle builder, and founder of Defensive Edge Training and SLR15 Rifles. For decades, he has taught armorers, instructors, military personnel, law-enforcement professionals, and responsible private owners how firearms function, fail, and remain serviceable.
Professional Biography
Sullivan brings approximately three decades of law-enforcement experience, including work involving special operations and training. He is best known for his expertise with the AR-15, M16, M4, and AR308 families, but his armorer instruction also extends to law-enforcement shotguns, bolt-action precision rifles, M14/M1-pattern rifles, and 1911 pistols.
Through Defensive Edge Training, SLR15 Rifles, and WeaponsArmorer, Sullivan has built a professional role that connects operational firearms instruction, armorer-level technical knowledge, institutional maintenance, and firearms manufacturing. That combination allows him to address the weapon as a mechanical system and as equipment that must support a trained user.
Armorer Education
Sullivan’s armorer courses go beyond parts replacement. They teach students to understand cycles of operation, inspection, gauging, component compatibility, maintenance intervals, common failure points, and the relationship among weapon configuration, ammunition, magazines, user input, and reliability.
This diagnostic approach is especially important for institutional armorers. A duty weapon cannot merely function when it leaves the bench; the armorer must determine whether it is safe, reliable, appropriately configured, and suitable to remain in service. That requires repeatable inspection criteria and the judgment to distinguish a symptom from its underlying cause.
Sullivan has taught these subjects to local, state, and federal law-enforcement personnel across the United States. The effect extends beyond individual students because an agency armorer may apply that knowledge to dozens or hundreds of firearms throughout a career.
SLR15 Rifles and Carbine Training
Sullivan’s technical philosophy also informed the SLR15 rifle line. The rifles were developed around lessons from training, maintenance, repair, and operational use, with attention to component selection, gas and extraction reliability, staking, materials, barrel specifications, assembly, inspection, and test firing.
Pairing rifle construction with training reflects a systems-based view: the firearm, operator, maintenance program, ammunition, magazines, and instruction all affect performance. A quality rifle alone does not create capability, and a trained shooter cannot compensate indefinitely for neglected or poorly configured equipment.
His carbine instruction connects that mechanical understanding with marksmanship, weapon manipulation, positional shooting, malfunction management, movement, transitions, unconventional positions, low-light work, and close-range employment. This helps students and instructors distinguish shooter problems from equipment or maintenance problems.
P&S Connection
Sullivan is part of the Extended Primary & Secondary Network as a P&S contributor. His technical knowledge and long-running training programs add depth to discussions concerning rifle reliability, armorer standards, maintenance, institutional firearms programs, and the connection between equipment and user performance.
The P&S Forum also preserves numerous after-action reports from Defensive Edge and SLR15 armorer courses. Those student accounts document the practical reach of Sullivan’s instruction and provide continuing reference material for armorers and firearms instructors.
Key Areas of Experience
- Law-enforcement service and firearms training
- AR-15, M16, M4, and AR308 armorer instruction
- Firearms inspection, gauging, and diagnostics
- Preventive maintenance and lifecycle assessment
- Rifle reliability and component selection
- Carbine instruction and instructor development
- Law-enforcement shotgun armorer training
- Bolt-action, M14/M1, and 1911 armorer training
- Rifle building and SLR15 development
- Primary & Secondary contribution
Selected Sources
- Law & Justice Commission MTU 8 — Greg “Sully” Sullivan
- Ohio Tactical Officers Association — Defensive Edge AR Armorer Course
- P&S Forum — Defensive Edge / SLR15 Rifles
- P&S Forum — Defensive Edge Training AARs
Profile last reviewed: September 10, 2026.
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Greg “Sully” Sullivan · Greg Sullivan SLR15 · Defensive Edge Training · SLR15 Rifles · WeaponsArmorer · AR-15 armorer · M16 armorer · M4 armorer · AR308 armorer · law-enforcement firearms training · firearms diagnostics · rifle inspection and gauging · carbine instructor · rifle reliability · Primary & Secondary contributor