The RR triggers are OK starting out but they wear out pretty fast (usually 3-6,000 rounds) and when they do they start to double. I prefer the Geissele SSA which will make it a full 10,000 rounds at which point it is time to replace the bolt, all the lower parts including the trigger and maybe the barrel. Any trigger you go with if after some wear it starts doubling I would not try to fix but replace at once as then you are in possession of an unregistered machine gun.