Penetration is to low:
Tested: Gun vs ~1cm thick wooden planks

• 6.5mm Silenced Main Gun of type 115: Penetrates easily
• .50cal Secondary: No penetration at all

Tested: Gun vs edge of Wooden box:

• 6.5mm Silenced Main Gun of type 115: Penetrates easily
• .50cal Secondary: No penetration at all

Please take a look on the penetration value of this gun, as it seems a bit to weak.
Also this Secondary .50cal has no ammo on the shooting range.