Gunnery Sgt. Justin Kratzer, Radio Maintenance Chief, delivers what looks to be a devestating to blow to Cpl. Jacob Brown, administrative clerk, during the controlled sparring phase of their 3-week long Martial Arts Instructors Course (MAIC) aboard Marine Corps Logistics Base Barstow, Calif., May 10. - Gunnery Sgt. Justin Kratzer, Radio Maintenance Chief, delivers what looks to be a devestating to blow to Cpl. Jacob Brown, administrative clerk, during the controlled sparring phase of their 3-week long Martial Arts Instructors Course (MAIC) aboard Marine Corps Logistics Base Barstow, Calif., May 10.