I.R. Co. rear sight

[firstflabn]

I've been at the military history research game for 30 years, though only the last four or five with WWII subjects (with the carbine foremost). I sometimes know where look and other times I puzzle out a search plan based on understanding how the organizations worked. Logistics in particular leads to insights on combat. We're all still basically ten year old boys with a foxhole in the backyard and a helmet liner hanging on the bedpost, but logistics happens before the shooting starts.

If you visit the Archives, don't get discouraged if you don't find it all the first trip. See the first visit as a scouting mission to figure out how things are arranged. The collection description says 18 cubic feet - that's alot; probably 60 or 70 of the four inch wide Hollinger boxes worth. I was excited to see the listing for unit histories - organization structure could give you the opportunity to prove me wrong with nothing more than one sheet with an org chart. And you know the military is going to show command structure. Hopefully you'll find bean count-type reports showing quantities of work done in various categories - maybe presented different ways.

On your mag catch question - I've never seen the MWO, but it wouldn't surprise me if it was only two pages - one sheet front and back covering the mag catch and the mag catch plunger/spring. You can find the requirements incorporated into the February 1953 edition of TM9-1276 which is all over the internet.

[firstflabn]

And one more for the Seattle Branch:

Record Group 156
Records of the Office of the Chief of Ordnance

Administrative History
The Ordnance Department was established as an independent bureau of the Department of War by an act of May 14, 1812. It was responsible for the procurement and distribution of ordnance and equipment, the maintenance and repair of equipment, and the development and testing of new types of ordnance. The Department was abolished in 1962, and its functions were transferred to the U.S. Army Material Command.

Records Description
Dates: 1940-50
Volume: 6 cubic feet
Records of the following installations:
Beaver, Oregon, Ammunition Storage Point;
Mount Rainier, Washington, Ordnance Depot;
Umatilla, Oregon, Ordnance Depot.
The records relate to administration, and are primarily correspondence, installation histories, and program files.