the glock bulge from my research (as a xd40 owner) was only really an issue as noted with 40, as well as 380
they left the rear of the cartridge at the feed ramp unsupported to aid in reliable chambering during cycling.
lee makes a kit called the "bulge buster" to take that out, but brass thats been fired in an unsupported glock chamber should never be resized and fired again in an unsupported chamber. i guess it increases the likely hood for failure quite a bit.
https://leeprecision.com/case-condition ... uster-kit/i dont recall reading that it was an issue with 9mm, or other calibers.
as also noted - there are a pluthera of aftermarket barrels for glocks that do not have said unsupported chamber issue with them that would allow safe usage of reloaded ammo in them.
one big perk is - 40 brass is *CHEAP* so you can cull out buldged brass easily and affordably if needed.
here's a pic i found on the web of the infamous bulge, aka the glock smile
and as you can see from this pic the difference between an unsupported and fully supported chamber based on where the feed ramp is cut to
hth