The .22 Automatic was used extensively by the RFC in Winchester rifles during WWI for training observers. It was usually used fixed co-axially to a Lewis gun for shooting at balloons.
Details of the purchases of rifles and ammunition and the way they were used are all in my Secondary Weapons book, Part 2.
Is it the same as the 22 Winchester Auto?
Pivi: Yes, that’s the .22 Winchester automatic cartridge. It and the similar Remington round can be distinguished by rim diameter, .310 in. for the WRA product, .290 for the Remington. Jack