I have had a few BSA scopes. one was a BSA sweet 22.
Cool idea and all, but realize that the drop calculations are based on one barrel length and a specific bullet weight and loading. Chances off it being dead on are slim.
They are an ok cheap scope, but one thing I find/found frustrating is that the eye relief on mine was very narrow. You had to be in just the right spot. Higher end glass has a bigger relief zone.