I would check the trigger spring first, if it was particularly fiddly and kept wanting to pop out you may have put the shell back together with the long portion of the spring which pushes against the gear box shell actually resting outside the shell (see pic... the position with the X next to it). Naturally it wants to pop out and rest in an un-tensioned position outside the shell.
The long part of the spring needs to be pushed over the wall and pressed into the shell behind the plastic safety arm (see pic.. the position with the tick next to it).
Sometimes you can actually use the safety arm to help keep the spring in place by keeping it in the auto position covering the springs long portion.
View attachment 56213
Auto works because in this mode it makes use of 2 springs to reset the trigger: the trigger spring and the switch block spring - however in semi the switch block is flicked out of the channel by the cut off lever and then waits for the reset of the trigger spring to return to its starting position.
Sometimes you can check to see if this is the issue with the gun fully assembled, peak through the hole in the receiver that the trigger protrudes from, some times you can see the gearbox and that piece of the spring sticking out where it shouldn't be.
- Other things to check
- Make sure the entire switch block assembly is sitting flush inside the gear box shell, especially along the top under the switch block and along the left side of the assembly.
- Check that the switch block spring is installed correctly - hooked on both the metal dowel and the switch block and that it is sitting straight (not at an angle) so that it allows the tappet plate to move freely back and forth above it.
- Ensure the cut off lever is installed correctly - your tendency may be to tighten this down but it must be allowed to move freely - tighten the screw down and then back it off by quarter of a turn (possibly less), it must be able to move free of any friction however not to the point that it is rattling around.
Hope this helps dude, a fiddly trigger spring which wants to pop out is one of the most annoying things about a v2, patience and an extra pair of hands can help, as it seems you were able to find the first time.
Worst case scenario is when the trigger and anti reversal latch springs are as stubborn as each other ?
