This.
There are two different insulators/spacers and two different screws to accommodate slight variations in battery dimensions (this is why most of my batteries match now) and different throw lengths for the switch... which is also adjustable from the gpin end as well.
If your v4 misfires suddenly (not autofire), check to make sure that the switch screw is tightened all the way. I'd also recommend locking the switch in your pocket. [emoji5]
Thanks cliffy, now I know I should order the insulators also. You are talking about the insulator of the switch?
I got one of my V4 switches when it first came out, and another a few months later.
If I wanted to see which one is the first batch, is there a reference of serial numbers? Could I assume the lower number was most likely the original batches? If I could be more sure which parts Id need, then I would not have to order 2 sets of each size and only the correct size.