The World War 1 M1903 Springfields used either the M1913 Warner & Swasey telescopic musket sight or target sights such as the Winchester A-5 or similar Lyman target scope. The M1913 W&S scopes were obsoleted after WW1 although some of the A-5 or Lyman equipped M1903's were used early in WW2.
The USMC put together its Scout-Snipers in 1942 and built-up the Model 1942 Sniper's rilfe using 8X Unertl target scopes and M1903A1 national match rifles. These rifles were used by the Navy and Marines. Some of the M1942 rifles were used as late as the Korean War. These rifles will always be found with the Type C full pistol grip stock.
The Army did not have any purpose-built sniper rifles at the start of WW2. When the M1903A3 rifle entered production, the Army decided to use it as a sniper rifle. This rifle was called the M1903A4 and used the Weaver 330 or later M73B1 sight (that resembles to Weaver 330). The M1903A4 may be found with either the full pistol grip stock (like the M1942) or a semi-pistol grip stock that resembles the SMLE No. 1 Mik III.
In early 1944, two experimental models of M1 Garand -- the M1E7 and M1E8 -- were type classified as sniper rifles to replace the M1903A4. The M1E7 became the M1C and the M1E8 became the M1D.
The M1C used a Griffin and Howe throw-lever mount with a rail that attached to the side of the M1 rifle receiver with three machine screws and two taper pins. The mount is off-set to the left to allow the Garand 8-shot clip to function. A leather cheek-piece is attached to the stock that allows both optical and iron sights to be used. M1C rifles may be found with either the M81, M82, or M84 optical sights. Differences in sights in the reticle: the M81 uses a simple cross hair; the M82 uses a post; the M84 uses a post and cross hair. The M84 scope is common and in later years replaced the Model 330 and M73B1 scopes on M1903A4 rifles as they became unserviceable. Approximately 4,000 M1C rifles were converted in WW2.
The M1D (ex-M1E8) became the standard Sniper's rifle post-WW2. The M1D used a special short rear handguard and barrel. The M1D was designed to be built-up by ordnance work shops. The standard M1 barrel was removed, the new M1D barrel installed (it had an integral mounting block, the rifle assembled with the short handguard, and the leather cheek-piece attached to the stock. M1C and M1D rifles were issued with the cone-shaped M2 flash hider. The M2 was replaced by the five prong T-37 in the late 1950's and early 1960's.
The USMC did not use M1D rifles until after the Korean War. Snipers in Korea used either the M1942 Springfield or the M1C. Early experiences during Korea caused the Marines to look for a better scope than the M81, M82, or M84 optics. The Marines settled on the Stith Bear Cub, a 4X scope with large W&E knobs that made audible clicks when adjusted. Griffin and Howe made up a longer scope mount with 1-inch rings for the scope. These scopes were produced for the Marines by Kollmorgen Instrument Co. and rifles fitted with them were called the MC1 or M1952 Sniper's rifle by the USMC. The MC1 (M1952) was supplemented with M1D's during the mid-1950's and onwards.