M4 SOPMOD Shop Upgrades

[Hazard]

By Gun Shop FIRST
Basic Upgrade (spring and piston head)
Basic Upgrade 2 (spring, piston head, inner barrel, trigger response)
Low Cost High Cycle Upgrade

Tagal ko nang gustong malaman kung ano ginagawa nila sa mga upgrade na 'yan kaso sa sobrang mahal nagdadalawang-isip akong sumubok.

[lifes26]

as far as i know pareho lang ng ginagawa natin ang mga iyan... plus cleaning and re-greasing. iyong iba plus polishing.