A little further
Now I have read the articles on scopes in Target Shooter 2009 and became reasonably confident that a Bushnell 10-40 was a good choice, read on and found ...beware parallax change...... moving objective to change parallax... risk all argon gone...... warning... an inert gas escaping .....how can I as a novice ensure parallax is 23 yards or 30 or 35 or 25 as variously described and which number of yards is good anyway? and by how much each go do I move ? Some say 1/4 turn anticlockwise others 1mm.
so now I know a Bushnell is a good choice .... parallax rejigging needs addressing before I proceed.