it depends on a lot of factors.is the gun pumped the same each time,is the scope mounted on the reciever or the barrell??
I had one that I could never keep on site.after a few very disturbing weeks tring to get it to hit the same,I finally saw my problem.
the barrell and reciver were moving indepently.the scope was mounted to the reciever and the barrell would move when the reciever wouldn't.with it like that you can never get it sighted.

if yours is all together and tight,you need to check the #of pumps you give.if you shim the scope,I would say to take a beer or coke can and cut little strips to skim with,you can use several strips if needed.the tape will mash thinner depending on how tight you put it.

Hope this helps!!<img src=icon_smile_cool.gif border=0 align=middle><img src=icon_smile_approve.gif border=0 align=middle>

I am not a hunter I am a whitetail population reduction specialest

remember keep your back to the sun, your knife sharp, and your powder dry.