there is alot of back of forth on it. Now all of my experience is only with the glock 10mm so take that into consideration. Some folks will say it could lead to issues but there are several folks out there (myself included) that do shoot .40 in a 10mm without any issues. i shoot .40 in my glock 20 fairly regularly using the factory barrel and mags and have never had an issue.
I know back in the day when 10mm ammo was virtually unknown to most gun shops, a work around was to take .40 S&W brass (which wasn't too common itself), a heavy bullet, and seat the bullet long. It would work fine in a 10mm. Never have tried straight .40
I had some of the original Norma ammo - wish I'd had a chronograph because is was some kind of hot.