Scope problem

[Allrightscud]

Hi, looking for some advice. My father had an air rifle which he and I use to shoot feral pigeons in the barn. I took it out the other day and it was shooting way off. I zeroed it and found it was shooting 18 inches high but still dead centre. I've used the gun many times before and it's always held its zero. Anyway when I tried to zero it I found that at the lowest scope adjustment it still shot 5 inches high. The only thing I can think of is the scope has been knocked but was wondering if there's anyway to get it back or is it useless now. It's a Tasco world class .22 with 1/4inch clicks at 100 yards.

[coalman]

Have you tried packing the underside of the front scope mount ring?

I used to use old 35mm camera film/negatives cut to size which acted as shims.

Loosen the scope mounts and slip a "shim" between the front mount and underside of the scope tube to raise the POA closer to the POI.

I used to do it years ago before dedicated air gun scopes were around and couldn't get enough adjustment as you describe.

[Oldfarmer]

Check the mounts have not slid back in the dovetail groves due to recoil and ridden up a little.

[Allrightscud]

So is it the front of the scope I'd need to shim up or the rear. Thats the bit I can't quite get right in my head. I thought the rear needed jacked up for some reason. Maybe because I was lowering the scope adjustment, but after your comment Coalman I've drawn it out on paper and it makes sense to me now. The scope front needs to be raised to bring it into line with the point of impact. Thanks Colaman, off to find some negatives.

[Allrightscud]

I took the entire set up off and reset the mounts and scope and managed to get it down to 5 inches from 8 so there may have been a bit of recoil slip.

[Allrightscud]

4 shims later it's sorted. Thanks Coalman.