When were Marine Corp sights first used?

My apologies for the misspelling of Marine Corps.

The rear slide insert with only the large aperture, the tall and wide front sight blade, and the large front sight protector.

RB,

Brophy or the Professor (John Beard) stated early twenties. I believe John added that they were ordered to be removed during overhaul in 1928 and thereafter. And they could be retained by special request.

Think I directed John to a rifle on GB once with the sights. After reading the rifle photos, he decided that the rifle still had the sights because it had never been overhauled and probably never left the ship it was on. Wish I had that one.

Lancebear

From Canfield's "An Illustrated Guide to the '03 Springfield Service Rifle"

Marines during WWI thought the m1917 sights superior the the 03's in many ways.

They ordered 10,000 sets (front blade and rear ap) from SA in Oct. 1918, first manufactured in 1919.

Sheet metal cover was produced for use with such sights.

Remained in service through at least 1936, and some have been found on original 1903A1/Unertl sniper rifles used during WWII.

Not doubting the other info, just what I read.