Also I can't verify it but I was told not to reload once fired that came from a Glock.
I don't know why just what an old reloader guy told me once. I guess you can identify it by the oblong strike on the primer.
Like I said Glock guys don't flame me I am just passing on what I was told once.
i have had some cases that were like what you are describing, i just sized them and they have been fine out of my xd, i guess that glock dont have a fully supported case and they swell some when they are fired
I have reloaded many .40 with some bulged cases and havent had any problems. I dont load my target .40s hot so that helps by keeping pressure down and I use a Lee die set that sizes the whole case which removes the bulge.
I have loaded and shot some hot .40s (155gr JHPs chrono'd at 1200 +/-5fps out of my G23) with no problem, but I only use once fired winchester brass that looks good.