I think 6x is fine for your shooting, Mark. I have variables on my guns, if I wanted to stretch it to the limits, my "yard" is over 500 feet deep. Most of my shooting is 30 yards or so, and I usually have my scopes at 6 or 8x.
My Bug Busters were bad right out of the box, like I said above, I couldn't get them to focus much over 10 yards. Which is too bad, because it was perfect for the gun I wanted to put it on, an older IZH 60. If the Leapers/Centerpoint doesn't work out, check out the Nikko Stirling scopes. In fact, check out the Product Reviews, Scopes and Mounts. I've got a couple of Leapers reviews as well as my Nikko in there. Might be helpful. Later.
Dave