I have just got a 2 shot adaptor, which I had found on flee bay. I have never seen these before but thought it would be good for my fn8. It was advertised as fitting the fn8, 12 and 19. Unfortunately it does not fit my fn8 as the scope grove is too wide for it to go on. Would any one know why this may be so, I am tempted to try to re-size the adaptor, any advice or ideas as I don't want to waste what seems like a good bit of kit.