i tried to mod the cs-6 i found and broke it so i got these for under 20$. i love the firefly rev-8 it still lights and works perfectly the Hyperfire just
Modded Nerf Hyperfire Machine Pistol black and Red | Etsy UK
Amazon.com: Worker Mod Incline Flywheel Update Kits for for Nerf N-Strike Elite HyperFire Toy Color Rose Red : Toys & Games