A lot of us have the Single Tens and you'll find some reviews on this forum, including one of mine. Great 22 revolvers.
A 22 mag is not only longer than a 22 LR, it also has a larger diameter case. Not that much, but enough to cause Ruger to bring out a separate Single Nine in the 22 mag, rather than try to make a Single Ten convertible. Oh, well, I'll probably just have to get a Single Nine to go with my Single Ten.