Looking through some extras today I found this. It has a nickel primer and is the typical REM-UMC round ball game getter load with the typical smooth cannelure about 3/16" below the mouth which has been rolled over the edge of the ball to hold it.
The “MARBLE” looks to be hand engraved, not sure why someone would go to the trouble, unless they were just practicing engraving & this was handy? The case has been notched at the rim edge, just at the “R”, and is not split.
Otherwise it is just like the other non-marbled example in the collection.
So questions, anyone seen others? Any other ideas, or guesses why?