5MadFarmers.com

First, the table:

A is plus 5,000,000
C is plus 5,500,000
B is plus 6,000,000
D is plus 6,500,000
E is plus 6,900,000
New is from 7,000,000 to 9,999,999


M1 rifle bolt is drawing number D28287. Plus 6,500,000. 6,528,287.

Now, we need to get the Federal Supply Group. For this, it's "Guns, through 30mm." So 1005.

1005-652-8287. That was the "Federal Stock Number."

When the U.S. decided other countries could play too, they adopted the country code. NATO claims it's "NATO Stock Number," but the U.S. created it, and it's the "National Stock Number." Which, unlike NATO, includes South Korea.

The U.S. gets 00 and 01.

1005-00-652-8287. That is the "National Stock Number" for the bolt of the M1 rifle.

Reverse the stream. 1005-562-1060-B003

Carve off B003 as that is the SNL these first appeared in. SNL-B is small arms, non-automatic. 003 is the M-1903.
Carve off 1005. That is the FSG.

562-1060. Lose the dash.
5621060.

Calculate possible drawing codes, using the conversion table above, in reverse:
A621060
C121060


We're clearly in the right neighborhood. C121065 is not long after. Ok, that opens up a can of worms.

Item Stock Number for that is B028-02-00070. What is that code? It's a dead code. From an abortive attempt to introduce a system which didn't survive. When that attempt ran aground, the Feds stepped in with the conversion system covered here. Another example would be drawing C64148. The pistol lanyard for the M-1911s. The ISN for that was B006-02-00050. Then that system was aborted and it used the conversion system covered here. 5564148. 1005-556-4148. 1005-00-556-4148. You know the drill.


Those dropped out of the system ages ago. They don't even know what it was. Nice neighborhood.