.22lr shot cartridges, that really sounds like a pointless invention!
I would have thought effective range would be about 5 feet!
Might as well throw stones...
Trying to get my head around these tiny shot shells, 9mm etc.
When you consider that even the most potent game loaded 12 bore cartridges today have a "realistic" effective range of 50 'ish' yds, what was the range of a 9mm shot shell?
I think back in the day I would rather have used something along the lines of the relatively powerful (for the day) Lincoln Jeffreys .22 air rifle for Garden Anti rat use etc.
Saying that, they were post WW1 I think..