Same with Guarder. Installing one in my HK 416 brought the velocity up from 395 fps to 420 fps. Got an extra 15 fps in my CA M15. Not sure what it did for my MP5, as I didn't have a chrony before I installed it.

Cool, that's good to know.

Best reported hop-up bucking are Garder clear or systema with a scs nub, Prometheus purple with H-nub or stock prommy nub and firefly soft bucking with firefly normal buffer rubber. Any of those combinations depending on aeg type and used with a good hop-up unit will achieve good result.

2 year old thread?
:p

Does anyone know what would be a good hop up rubber for a KJW m4? Also how do you get to the rubber on that gun?y