We are currently having some fun shooting sporting air rifles with scopes at various targets in our club, but our indoor distance is fixed at 10 meters.

Not all of the scopes that we have "dug-out" are AO or will focus down to 10 meters but they are good scopes that work well at longer ranges and if we can adjust them to give a sharp focus at this shorter range it would enable us to make good use of the ones we already own.

We have been told by a few "passers-bye" that it would be possible to adjust the front lens on our non- AO scopes to convert the focus from the factory set distance ( 30 yards or so?) down to 10 meres.

I notice that the front lens on our scopes do have a screw thread ahead of the front lens, so maybe this allows the lens to be moved in or out to adjust the focus down to 10 metres? I also notice that the scopes are nitrogen filled and suspect that "tinkering" with this lens could release the gas?

If anyone has any succesful experience of making adjustments like this to a rifle scope and can advise us how to do it we would be very pleased to hear from you!