A few observations that may (or may not) be relevant:

1. There was no Naval Ordnance District. The Navy's procurement agencies were the Bureau of Ordnance, abbreviated as BuOrd and the Bureau of Supplies and Accounts, abbreviated BuS&A.

2. The markings aren't factory but appear to be cut be a pantograph machine very similar to the NYMI and "Red Navy" guns.

3. Prior to WWII Navy contracts had No or Nos prefixes. During WWII these changed to NX.

4. It would be helpful if one of the owners actually lettered one of these so perhaps we could learn the destination.

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Kevin Williams SWCA1649 HF208