If you were to own an Automatic weapon, you should forget about the MP5, as is has no other use than to make head shots on a human. For the same amount of money, you should go for the M4A1 carbine. Although it dosen't have the accessory rails that the A3 and new A4 does, it is semi and fully auto capable. This weapon will not only provide mroe enjoyment fo rthe same amount of money, it is a 5.56 round, which is leaps and bounds above the 9*19mm.
On a further note, I have been told that if you use a Class III firearm in a defensive situation (even if the court decides in your favor) you will never see that weapon again.