The P227 is described as:
High-powered meets high capacity.
It can be found in northern Malca province, under the statue of Santa Muerte at a concert venue in the hills. The “El Chido” mission can be found nearby if you’ve got this far in Malca. The weapons case is inside a small shop just inside the entrance to the venue area.
I approached from the road, which brings you in from the north. After taking out the two enemies at the first road checkpoint, I then patiently used sync shots to take down the others near the entrance to the venue. However I think an easier route would be to approach the shop directly from the hills to the east, and sneak in the back door and take the weapon.
This pistol confuses me slightly. It’s stats are similar to the P12 (found in Tabacal), but generally they’re not that good.
The description is weird, because it’s not a very high capacity gun either, with only a 10 round .45ACP standard magazine and a 15 round extended mag option (in Koani). But really, I’d say the P45T you start the game with is a better pistol, and the same calibre.
Personally, I’d never use this gun, and I think there are definitely better pistols, and more specialised pistols out there for your needs.