Interesting article by Bruce Canfield on the M1903A1/UNERTLE USMC Sniper Rifle.
An Official Journal Of The NRA | The M1903A1/Unertl USMC Sniper Rifle
Adopted by the Marines after Pearl Harbor, the combination of the M1903A1 Springfield with a Unertl riflescope was arguably the finest sniper rifle of World War II.
www.americanrifleman.org