Just did a spit and polish tune on an old airsporter (o-ring head). Soft spring as it's for my son. Shoots fairly nice @ 7 FP.

Open sights zeroing is a bit of a challenge though - about 6" high at 15 yards on minimum elevation Just about a foot at 25 yards - the zero point is now just inside the top edge of the foresight hood, i.e. about 1/4" above the top of the blade...

Barrel looks perfectly straight / in line, sights seem the right height from the bore.

All I can think is the weaker spring is taking some slam out of the action, and as a result there is no piston crash to pull the action down...
Or the crown is pi55ed down there in that counterbore.

It's actually quite accurate, just way too high...

What gives ?