- MarkHolloway
There's an old, faded stencil that says, "PJNIM" if that means anything. Photo shows where containers are joined.
PJNIM (or perhaps P1NIM?) is the Code Symbol or Ammunition Identification Code for this ammunition item.
P means it was cataloged in SNL Group P_. The catalogs were P-1, P-2 and the like, I don't think there was ever a letter-letter designator. Catalog P-1 covered Projectiles, separate loading, 6-inch to 240mm inclusive. Others in Group P were propelling charges and antiaircraft artillery ammo, and others.
NIM would be a designator indicating a particular stocking arrangement, including both the ammunition and the packaging.
The 3.25-inch target rocket someone mentioned was cataloged in group S-9, S9B _ _ to be exact, with the motors as S9D _ _.
If there's any chance of finding clearer stencils, that would say exactly what this is for.
KL