His military experience quickly taught him that there is more to tactical marksmanship than merely squeezing the trigger. Utilizing his years of experience, McNamara developed a training methodology that is safe, effective and combat relevant and encourages a continuous thought process. This methodology teaches how to maintain safety at all times and choose targets that force accountability, as well as provides courses covering several categories, including individual, collective, on line and standards.

While serving as his Unit's Marksmanship NCO, he developed his own marksmanship club with NRA, CMP, and USPSA affiliations.  Mac ran monthly IPSC matches and ran semi annual military marksmanship championships to encourage marksmanship fundamentals and competitiveness throughout the Army.

He retired from the Army's premier hostage rescue unit as a Sergeant Major and is the author of T.A.P.S. (Tactical Application of Practical Shooting).