This video is still good for the latest patch 13.5. No changes.
Materials needed.
MP-133 (found in raid, barter or buy from Jaeger. Must be above 60% duribility.).
MP-133 custom plastic forestock with rails (hard drive bater from Mechanic)
NcStar tactical blue laser (Skier level 1 purchase) Zenit RK-6 foregrip (Skier level 1 purchase)
MP-133/153 plastic pistol grip ( Found in raid or buy from Jaeger)
ME Cylinder muzzle adapter for the GK-2 ( purchase level 1 Jaeger)
GK-02 Muzzle Brake ( found in raid but eventually available from Jaeger at level 3 or 4)