[Blind Sniper]

I would recommend the electronic bolt and not the M, but everyone has their preference

 

[Blind Sniper]

I use a lot of aftermarket receivers like AA, AirsoftPro or maple leaf. I never really have receiver issues though. If the pull was tight or hung up, I’ve learned that some cylinders don’t have a wide enough slot for the Bolt fitting. But there could be other small issues. Easily fixed as Mr. Sword said.