The PP19 is described as:
The Bizon, a veteran of the Caucasus.
You can get this in eastern Agua Verde, on a boat moored off a beach. There are enemies on the beach and on the boat. The weapons case is on the deck of the boat.
You don’t necessarily have to approach the boat from the beach to the north, but if you do you can kill the enemies there without alerting those on the boat. Either way, you’ll need a boat to get to the boat.
You could try and snipe the bad guys on the boat from a distance, or use sync shots, but as soon as they’re alerted they’ll take cover and you’ll have to move in close anyway. They’ll also radio for reinforcements which arrive at the beach, so it’s best to just get on the boat to take them down.
The PP19 was my favourite SMG for a while until I picked up the P90 (in La Cruz) which is my overall favourite. But the PP19 definitely has a few things going for it as you may know if you’ve ever picked one of these up from a fallen enemy.
While there’s no option for an extended magazine, you don’t need one. The regular magazine has more ammo than any SMG or AR with their largest magazine upgrades at a huge 64 rounds. It also has very clear iron sights and is surprisingly accurate with little recoil.
It really is a very good gun. Slap an optic on it and that’s about all it needs. It’s good to go and I highly recommend this SMG!