I am selling a Polarstar jack'd KWA SR7. I have modified the gun to accept standard AEG one-piece hop up chambers. NOTE: Putting the upper receiver on the lower receiver is simple, but takes patience the first time. After then, it can be assembled as quickly as any other AEG. If purchased, detailed instructions will be given. The gun itself is roughly 6 months old and has seen only a handful of games. The Polarstar Jack system is a month old, and has been fired only a little over 1,000 times (can provide FCU photo). Without the Madbull extensions, the shorter barrel is used. With the Madbull extensions, a standard M4 363mm barrel is used (included)(new)(not pictured) INFO: (Includes everything listed) External: MFT Minimalist Stock PTS style pistol grip 7" Metal outer barrel Magpul AFG Magpul rail panels Madbull 2" outer barrel extension Madbull Gemtech barrel extension Buffer tube cut for easy stock removal and FCU access INTERNAL: Polarstar Jack Metal HopUp Chamber with 7" inner barrel Lonex HopUp (not pictured)(new) Lonex 363mm barrel (not pictured)(new) Adult built and owned. Gun feeds and functions flawlessly. Any questions please contact me. I pay the first $10 of shipping