Indentations on ZULU 10 Gauge Brass Shotshell

There is a ZULU 10 gauge brass shot shell up for auction on Gunbroker. ( … =283102863 )
The second and third photos in the auction show rows of four indentations, repeated every 90 degrees or so, around the the case. Does anyone out there know if they had a functional purpose, or were they some sort of trade mark?

I believe the dents were to help hold the top wad in place when they were reloaded.

I was kind of thinking the same thing except that I would expect the indentations to be a little closer to the case mouth. I do have a steel Soviet made 12 gauge shell that uses a plastic top “cup” that leaves the last centimeter or so of the case empty and has no crimp at all. It seems like a waste of case capacity to me. I have been told that they are for singles and doubles only, they supposedly don’t work well in repeaters.

Curt, this cartridge was made by Kynoch and the indentations were intended to secure the wad, which is rotated while is pressed into the case. This improvement was patented by G. Kynoch in December 16, 1881.

Thanks Fede!
That explains the first indentation in each row, are the other three dents for the the shooter of short chambered shotguns, so the case can be trimmed?
If anybody has the patent, I would sure like to see it.

Curt, the wad was positioned at any of the corrugations according to the varying sizes of the charges of shot used.

Ah-ha! I hadn’t thought of that. I wonder how well the patented Kynoch/ZULU system worked. It obviously never caught on.