The Extended Mag II attachment will increase the gun's magazine size to 15 rounds, making it easier to get multikills with the 9mm between reloads. As for range, use a Long Barrel to extend your ...

We don't have many attachment options for the Sirin 9mm, but what is on offer here is ... You'll also want to throw on Extended Mag I to increase its magazine to 40 rounds, which should be enough ...