The M1D was the final adopted form of John Garands sniper M1 rifle, originally the M1E8. It was intended to be a kit issued in the field to add optical sights to any rifle deemed worthy, and retained that capability in a slightly different form than originally intended. Garland’s initial plan was to design a sleeve that could fit over the barrel of a rifle, with a scope mounting bracket – the final production version instead used a new whole barrel with the scope mount integrally attached. However, this new barrel was still a part easily installed by a field armorer.
The scope was offset to the left of the receiver so as not to interfere with the Garand’s clip loading, and issued with a leather cheek pad to give the shooter’s cheek weld a matching offset to the left. The scope used with the M1D was the M84, a 2.2x optic with a simple vertical post reticle and hinger metal covers to protect the windage and elevation adjustment knobs. Accuracy of the M1D was not substantially different from regular M1 rifles, with its advantage coming from magnified optics rather than improved mechanical accuracy.
The M1D was adopted too late to see significant service in the Korean War, and would serve until replaced by the M14 and M40 rifles.