It is a Mk 1, and a nice Mk 1 as well. Detune would deffo be needed coil snip snip.
I don't like .22 as much as .177 because it is
1. Fat
2. Slow
3. Loopy
On the other hand, it is nicer to load, and it wallops things nicely. I don't shoot critters so I haven't a use for one really. But maybe I shouldn't be so narrow-minded.