I enjoyed this attachment so much on my Trion and saw such a bump in performance that I updated it to fit a 16mm outer diameter barrel. This was created specifically to replace the stock SCAR on the Harrier. It drastically improves the already amazing groupings. All original hardware the OG creator used in his post.

(Extra Hardware Required)

From Original Poster Takes 9 F683ZZ (3mm x 7mm x 3mm) flanged ball bearings and 9 3mm x 14mm steel pins. These can be had on Amazon, AliExpress, and numerous other outlets.