Great mod and I do love this range BUT the button on this particular v3 is rubbish. Took it apart twice to try and resolve an issue where the mod would only fire is you faced a particular direction and the moon was full. In the end I flipped the firing pin over which made the throw shorter and that helped. I've read of other people sending theirs back to VC and having the pin replaced.
Spend the extra and get the engraved special edition as it has a more mechanical feeling button and is 1, easier to fire and you don't need to be a power lifter to press the button and 2, fires every time without hassle. If you are spending this amount of money you don't want to mess about taking things apart. Spend the extra £10 and get the better button.