Mine shoots 1" off the normal place with a clean barrel, however, I know where that shot is going to hit thus I compensate for it on the initial shot when hunting or target shooting.
As for the WD40, I wouldn't have a can of it on the place, but some people like it. I think they mainly like it because it is cheap & easily available....
I prefer Ballistol to just about anything & all I have used for the past 5 years or so.
I ran a little test of my own a few months ago. I took about 12) 16 penny nails & ground a flat spot on each one of them & then drove them into a 2x4 just enough to make them stick. Then I took each nail & marked what I lubed each one.
Ballistol Non-Aerosol / WD-40 / Break-Free / T/C Bore Butter / Natural Lube 1000 / 30 Wgt. Motor Oil / Rem Oil / Ballistol Aerosol / My patch grease / My Liquid Patch Lube / Lehigh Lube / MooseMilk
The best rust inhibitor of them ALL was the 30 wgt motor oil. #2 place was Natural Lube 1000, # 3 was a tossup from my patch grease, the Lehigh, Break Free, and Ballistol.
Now this was left outside in lots of rainy weather, but not IN the rain, just exposed outside under roof in an open shed. None of them rusted for the first month. Then about 2 months they were starting to spot. In 3 months it was getting along pretty good. 4 months later the 30 wgt. motor oil Definately holding up the best but is just now starting to rust.
I didn't expect my liquid patch lube to do well in this as it is a patch lube, not a rust inhibitor. Nor did I think the Lehigh would do well& it did nothing great. The others did about as I expected with exception to the Natural Lube 1000 doing better than I expected.