Thanks for the replies guy's,
I have a decent scope on my S200 (Bit heavy and old but its brill in low light) a Kassenar 3to9x56.
I reckon it was just my range estimation as the pellet hit perfectly in the centre of the crosshairs just much further down than where I anticipated.
I did as Stealthy suggested and at 6 mag pellet scuttled pellet, while being scuttled by another couple bang on the crosshair centre Changed to 9 mag and the impact point was bang on line, but pellets landed down the centre post by a quater of an inch or so. So even with that slight shift, my range finding was a