It reads THE ELTERICH RIFLED BULLET SHELL / E.& CO. PAT. APR. 23 said:
These were actually made by STevens A&T Co.
They came in 3 different models.
One was for repeating shotguns.
#2 was for SxS w/an extractor.
These both were chamber length only.
The #3 had an extra inch (?) of 'bbl' out the front end.
Though you could spec order longer lengths.
10,12,16 gauges.
The #1 and #2 in 32S&W only
#3 in a variety inclu the 32-20,,10ga #3 in 38Spec.
Some cals in smoothbore.
The slots on the sides of the brass hull were supposed to flex outward when fired and center the hull in the chamber for some accuracy. Likely part of the Patent.
Marbles made a lot of rifle cartridge adaptors.
I have (somewhere) a couple of the Hoffer-Thompson .22short practice cart for the 1903 Springfield rifle especially adapted for them.
They must have been a real pain to work with, loading and reloading. Plus BP powder ammo trying to keep them clean and rust free.
Neat idea though.