Just wrote an angriesh email to gearsofwar about their shitty jr2 kimera grenade I bought, pile of shit. Either I got a dud or the entire range is a pile of shit. Watch this space for updates...
speaking as someone who did spend £10 more and get an xl burst, it's also not that reliable, it's a well made bit of kit and an interesting design, but it has a habit of popping o rings out/detonating the moment you fill it.