Terry,
Ahh more information. If I"m understanding you it was shooting fine before you loaned it out. If it shoots fine with open sights I don't thin it is a bent barrel. If it was bent then you'd have problems with windage on your rear sight too...at least I would think. I'm not familiar with the Tasco Golden Antler but are you sure it is airgun rated? I think the AR1000 is a pretty powerful gun shooting in the 1000 fps class. Depending on how well behaved it is, meaning how violent the recoil, you may have destroyed the scope. I've usually seen them go blurry or the crosshairs get messed up but I think that your symptom may also point to a toasted scope. I also think that if you had this scope on a 460 then it didn't live a comfy early life either. I think the 460 has a pretty decent kick to it as well.
It wasnt' dropped or anything was it? I would guess damage to the scope/bent tube would be evident?
Andy Wong aka larspawn