Originally Posted by SSGN_Doc
The rim diameters are:
9mm is 0.394
.40 is 0.42
.45 is 0.480
Using bore diameter can be deceptive, because the 9mm is a tapered case. The difference may not be enough to harm reliable extraction, but that would be my concern based on breech face dimensions already possibly being a bit generous.
I would also think a stiffer recoil spring may be needed for the 10mm since it is a higher pressure round.
The 10mm is a high pressure round (in many loadings). With the reputation Glock already has for case failure with the unsupported chamber, do you think it is a good idea to leave that much more area unsupported?
The 9mm and .40 shell plates for reloading are almost interchangeble. That is how close the base diameter is. Try resizing a 10mm (or 40) case in a .45 shell plate. You will rip the head off more often than not.
Storm Lake and some people may tell you it will work, but I prefer to use the appropriate slide for that job. I have a G-20 and plan on getting a .45 slide to ad to the versatility of the gun. I already have .40, .357 Sig and 9mm conversion barrels for it. They work. The 9mm uses a lighter 10 lb recoil spring because of the slide mass.