Silverback variable mass piston for SRS & TAC-41

How to assembly and fine tune your Variable Mass piston for Silverback SRS-A1 pull bolt. Excel spreadsheet link for SRS & TAC-41: https://www.silverback-airsoft.com/xls/silverback_variable_mass_piston.xlsx Music : Mr Surga - Project 1404 - Mayz gowd lalala https://soundcloud.com/surgape/mayz-gowd-lalala