Thanks, Ed. I appreciate the mutual appreciation!
A colleague and fellow WWII collector in Wales gave me some very strong leads last night.
Here are some early 1947 War Department drawings of a "Bag, BG44, with Carrying Strap", created by the QMC.
Look at the shape and then look at this new photo I just took.
While the front of my bag has some folds that have stiffened with age in that semi-collapsed shape even more than intended, it is not supposed to be rectangular. Fully stretched into proper shape, it is a polygonal shape.
I am 99% certain that what I have here is a Navy version of the same bag, or same bag design principle or style, with both of them (the BG44 and this one) probably built to older federal specifications. The polygonal shape, the front flap with two straps, the insert, the carrying strap, and especially those two wing-like flaps to keep the weather out of the seams between the front flap and the sides of the bag are all either identical or very similar. The BG44 drawing does not include the cast iron or steel corner supports on the bottom of my bag, and does not have nearly the same heavy duty D-rings and buckles, and my bag does not incorporate a carry handle at the top, but those are negligible considering the general shape, design, and principle.
Note that the date of the Revised Drawing is April 1947, but the date of the original drawing is built into the original Drawing No. at the bottom: 2-3-33. And it was part of a set of drawings made between 2-3-33 and 2-3-38. (Interesting to see "War Department" on a 1947 document, but it wasn't dissolved until late in the year, when the Army, Air Force and of course the Navy were made separate services under a cabinet-level Department of Defense.) That original drawing date confirms my suspicions about this bag being possibly even older than WWII.
As a side note, I am scratching my head seeing what I always took to be Signal Corps nomenclature (BG- for Bag, CH- for Chest, CS- for Case, TE- for Tool Equipment, TL for Tool, etc, link to full list on Radionerds site
here) on a QMC document. I have never seen that before. In fact, I have never seen any other part number from any other technical branch use that nomenclature.
The "44" in BG-44 is a model number in Signal Corps parlance. The Signal Corps had over two-hundred types of bags, all with a unique identifier. BG-1 through BG-216. The BG-44 was used to carry various toolsets, including TE-21, TE-27, TE-36, and TE-41.
Here are some actual photos of a BG-44 from the Radionerds site.
Note that it follows the same pattern as the QMC drawing and has even taller pressboard inserts. But, it doesn't have cast iron or steel corner supports, the straps and the body are all the same flimsy cotton canvas - as opposed to being stiffened with impregnated fluorocarbon or wax, no extra heavy duty D-rings and buckles, and - there are no anchors on the hardware!
What I think is happening here is that the technical branches of the War Dept, including the Navy, the Army QMC and the Army Signal Corps, were most likely following the same federal specifications for a tool bag of this type, first drawn up in 1933, and then the QMC borrowed the Signal Corps nomenclature in 1947.
Either way, it is one helluva sweet old tool bag.