In the OP, you mention experience with 10mm. Were you shooting a 20 or 29?
If the 21 is your first full size large frame Glock, there is a decent chance your fingers are placed just differently enough to induce some type of mechanical force transmission changes. If you were dead on with a 20, though, this observation becomes less relevant.
Last edited by samurairabbi; 03-19-2013 at 00:05..