Complex sentence: He served in the US Marine Corps from 1986 to 1990 with 2/9 STA Platoon as both a recon Marine and a Scout/Sniper, and was honorably discharged at the rank of corporal.
Split into simpler sentences: He served in the US Marine Corps from 1986 to 1990 with 2/9 STA Platoon as both a recon Marine and a Scout/Sniper. He was honorably discharged at the rank of corporal.