Re: B.C. variances for Accubond bullets?
The differance in clicks between .520 and .580 at 500 yards is only a couple as you stated. If you are using a 100 yard zero and udjusting from there, that could throw you off IF it is slightly off. Alot of shooters think they have a 100 yard zero and dont. In other words, you may be trying to zero on a 2" circle at 100 yards and if youre hitting 1/2" high of center, it seems like a perfect zero. In reality, a 1/2 off at 100 yards makes for neccesary adjustments at 500 yards.
Try a 300 yard zero. Then goto 500 yards and check that against a calculator. 1/2" off at 300 is still 1/2 off at 500 yards. 1/2 at 100 could be inches at 500 yards making you belive your BC is lower than it should be.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.