During WW1, and before, the various bits of the Army had their own systems. Within the QM itself there were multiple with "clothing and equipage" have their own, as did "transportation." The Ordnance Department didn't have any. The Medical Department used Medical Item Numbers for their Specifications.
After WW1, the Army itself stepped in with United States Army Specifications.
This left the various bits with a problem. How do you develop and test something without getting it adopted as a United States Army Specification? They introduced "tentative" specifications. These were dated.
- blanket.jpg (21.4 KiB) Viewed 439 times
That is a "Blanket, Wool, M-1934." Made to "Tentative Specification June 5th, 1935." Contract was dated July 8th, 1935. "Tentative Specification June 5th, 1935" replaced "Tentative Specification February 20th, 1935." The M-1934 wool blanket was formally given a USA Specification, 8-111, on November 12th, 1938.
- Raincoat.jpg (21.07 KiB) Viewed 439 times
That is an M-1938 raincoat. "Tentative Specification September 4th, 1940."
- Raincoat-2.jpg (35.91 KiB) Viewed 439 times
That, too, is an M-1938 raincoat. "Tentative Specification P.Q.D. 7, December 23rd, 1940."
See the switch? They went from Dated "Tentative Specifications" to Depot "Tentative Specifications." When? Between September and December of 1940.
- sleeping.jpg (43.97 KiB) Viewed 439 times
Bag, Sleeping, M-1940. Dated "Tentative Specification October 18th, 1940."
- sleeping2.jpg (33.38 KiB) Viewed 439 times
The next revision of the Bag, Sleeping, M-1940 was the "A." Depot "Tentative Specification P.Q.D. 152. March 21, 1942."
- Field-1.jpg (19.46 KiB) Viewed 439 times
That is a Jacket, Field, o.d.. Dated "Tentative Specification October 7th, 1940." 11 days before the M-1940 sleeping bag specification. Notice the sleeping bag had a model-year whereas this doesn't? The sleeping bag had a predecessor.
- field-2.jpg (22.4 KiB) Viewed 439 times
Jacket, Field, o.d.. Depot "Tentative Specification P.Q.D. 20. January 1st, 1940." Replaced Dated "Tentative Specification October 7th, 1940."
It all makes sense when you understand it.
- Field-3.jpg (15.62 KiB) Viewed 437 times
Depot "Tentative Specification P.Q.D. 20B March 17th, 1942."