Maruyama MP9 - Winter Spring Efficiency Test

Red: Text had some form of heating. Blue: Text was at ambient temp. 40 shots/test. No ammo used. Mag 4 had a cold magazine, warm propane bottle. Mag 1 had a warm magazine, cold propane bottle. Top results were done with cold mag and cold propane bottle Winter Recoil Spring: https://www.aliexpress.us/item/3256808666921571.html?gatewayAdapt=glo2usa Custom Spring Specs: Wire Diameter: 0.97mm OD: 11.16mm ID: 9.01mm Free Length: 25.63mm Compression: 16.23mm # of Coils: 6 Total # of Coils: 8 Black Bumper was 1.5mm thick rubber pad.