The Beretta is a good quality pistol, the price is quite nice for a full size M96, but the 40 S&W is a poor choice I feel.
I am not a fan of the 40 S&W. It is a high pressure cartridge that is already 'max-ed' at factory pressures and, in my opinion, runs on the edge of pressure versus performance. The 40 is not the 38 Super, which while near 'max-ed' at factory pressures can be loaded even further up the pressure ladder, seemingly without problem.
If you had said you had found one in 9mm, I would say: buy up a couple of thousand rounds of surpluss 9mm ammo and have a ball, so to speak..... However, that being said I often see adds for large amounts of 40 S&W ammo on the back of the Sportsman's Guide and other major suppliers.
If you reload, it is a different story. I believe that even the 40 can be reloaded sanely, at reasonable pressure levels and still give you enough out the end of the barrel to be useful. jmtcw.