I have a Kestrel 3500. I followed the mfg. info. on how to calibrate it (I think). Using the local weather station to check barometric pressure, the barometric pressure in the Kestrel will correspond to the weather stations' reading, but the altitude will bounce as much as 330'. (usually reading higher than what the altitude actually is) How this affect the actual poi of the bullet when using exbal? (hoping to get an answer without having to run more bullets down the gun). FWIW, gun in question is .257 Wby shooting 130g Wildcat R.B.B.T. ULD @ 3280 fps, verified bc .635, sight height 1.750" The gun was sighted in @ 300 Yds.