I was going to suggest a Browning Hi-Power until you spoiled it with the $500 budget... 
They make them in 9mm and .40 S&W but they're expensive to buy new. You might be able to find a nice used one, though...
The Hi-Power was one of the first High Capacity 9mm pistols to come into the mainstream market with popularity. They are notoriously reliable and lots of cops on many departments first transitioned from wheel-guns to the Hi-Power. They are still a fantastic weapon, even by today's standards...

They make them in 9mm and .40 S&W but they're expensive to buy new. You might be able to find a nice used one, though...
The Hi-Power was one of the first High Capacity 9mm pistols to come into the mainstream market with popularity. They are notoriously reliable and lots of cops on many departments first transitioned from wheel-guns to the Hi-Power. They are still a fantastic weapon, even by today's standards...

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