Adds in various attachment for Contractor .308 sniper rifle

Most of the attachment is aimed to decrease recoil kick, at the cost of heavy accuracy penalty.

• Unique barrel extension
• Unique stock
• 2 new handguard, 2 reused handguard
• Extended magazine, that allows rapid single-fire action

PD2 skin support: texture and code

Thanks to carl ruins everything's help on retex and skin texture.
He did the best of what he could to retex the source texture, so the custom attachment blends decently with Payday 2 Contractor.308 looks.

As Always,

Requires BeardLib
Requires WeaponLib

> Put in "mod_overrides" folder

Known Issue: