Yesterday I noticed that my CA M4A1 would fire in full auto even when set to semi which was rather odd. I haven’t opened up the mechbox for months so it’s not like a spring would have popped out or something, anyway after taking it apart I found that the trigger contact rail broke.

Luckily for me I had an extra (pictured above and to the right), after installing it into my gun the rifle fires in semi again woo!