My #24/ 40SW mikes .590 on the button, (also the 9mm conversion for the #24) the #34/ 9mm mikes .570 on the button, the hole in the slide is .005 over.  Like to check some smaller glock 40SW's

Hi Al
got out the mikes this morn.
17-L barrel .570, barrel extention? .392, breach face .3955 (new slide).
23 .40   barrel .589, barrel extention  .425, breach face .430.
23 9mm barrel .590, barrel extention  .4285.
both model 23 barrels are aftermarket.
lower extention .377+ or - on all three barrels.
later

the #23 was originally .40, so that makes sense. .355 barrel=.570  .401 barrel = .589/ .590
9mm wall thickness actually a little thicker then .40sw, .1075 vs .095
Similar pressure, possibly Glock just didn't want people swapping the barrels?