SD:M3 OP (203mm)

 is a United States Support unit.

Overview
This M3 carries the Forward Observation Team of a 8-inch howitzer M1 Battery.

The earliest designs for this Howitzer were first developed in the 1931 but the Great Depression slowed down development of the artiilery piece with the Howitzer being designated in 1940. Each battaion of 8-inch howitzer are organized into three two howitzers batteries. These Howtizer were used as various artillery missions except for close support.