While goofin' off at the gunsmith today, we took a magazine for my Beretta 96F, and compared it to a 9mm surplus high capacity magazine and found them identical in every way except the mouth of the 9mm was just a hair more narrow. We took a pair of pliers, and opened it up some, and found that the 9mm magazines work just as good as the .40 S&W mags. Never jammed, and as a bonus they held 11 rounds instead of the usual 10. I bought two of them, and will probably buy more IF> It isn't illegal to use these magazines (Pre ban, military surplus) in a handgun niether marked in the same caliber, nor gun. I figured that since I'm not manufacturing anything, only doing a 1 or 2 millimeter "adjustment", that I'm still within my leagal 'rights'. Can anybody comment on this? The magazines are cheaper anyway, and they hold an extra round. To me, this is a win-win situation. Any input is appreciated.