I use CH and must say I have not had much issues with it. I have a steyr with rail and use it but I calculate my distances from the saddle of the scope. easy to cal the height. 1/2 scope tube + 1/2 barrel diameter + space between the two. I figure that the drop over the 1st 40cm of barrel length (if there was no barrel) would be negligible so I start at the saddle for ranging and CG clicks. Atmiospheric changes would make more diffs down range than that little bit of diffs.
Oo. and wit the scope sloped it is so little. It is really only to alight the scope optical centre with the zenith of the pellet travel. You anyways adjust the crosshairs to this effect if you did not have a rail