My understanding of Glocks was that according to Massad Ayoob he thought that Glock had got everything right with the .45ACP's especially in the G30. Which could also be an option.
I have a G30 that has be fitted out with springs, connector, KKM barrel and sights and the darn thing is super accurate. It stays up with a Para 14-45 race gun that I had made a few years ago. Stays up with but does not surpass.
The G21 should be a good choice.
