I have a Swaro Z3 @ Swarovski right now having the parallax adjusted down to 50yds. Gonna put it in a 22LR.
Would have liked to go lower, but that's as far as they go. I know, Swaro on a 22LR - overkill, but what they heck, loonies gotta be loonie!
Back on topic, I have several Z3s. Awesome glass. The Z3 was my introduction to the Swaro world. Since then the number of Swaro's I own out numbers any other brand 2-1. As another poster states, the ZZ (and up) are better suited to heavy recoiling guns, or those with a sharp or snappy recoil. The higher end (Z5 - up) have a much more robust erector. Some will never have a problem with the Z3 and recoils. Others will piss and moan because the Z3 they have on their XXX 'loud-n - boomer' failed on them XX times, even though they may have been forewarned.