3 or 4 inches shouldnt equate to a clean miss unless your distances were long. A perfect example of a reason to get a good scope.

They are cheap, but I will have to say that I have had them on my rifle, and still have one on my ml, and they have never lost zero. I have never had any problems with them and they have done their job for me, so IMO, they are just as good as any of the others, and yes I have used others that were more expensive and of better quality, but as long as they hold zero and allow enough light in, I would use a cardboard papertowel roll with dental floss crosshairs. Tasco is no longer in business.
you still should have hit the deer if it was shooting 3" to the left, unless you were neck/head shooting. I am not doubting that the scope was off, I am just saying that 3" is not that big of a deal on a whitetail, unless it was a pretty good poke.