Canted base, applied ballistics

[Intell]

Does a canted base mess with AB? The reason I ask is after getting a solid 100yd zero on a particular rifle, I moved to 300yds. Velocity by Mag speed, scope height 2.75 over bore and all the other inputs. At 300 it calls for 2.83 up. It actually needs 3.75 up. When I trued the velocity it was showing 200fps less than mag speed says I'm getting. So I change scope height input to down 1.5 range and my 300yd shows a true come up to the actual 3.75 needed. The only thing I can think of is that a canted base possibly messes up the scope height input. I've noticed this on other guns in the 500- 700yd range, then when I true velocity it shows way slower than Mag speed says. Anyone else run into this? I have another rifle without a canted base and it seems to be truer with AB.

 

[hogpatrol]

I've used AB & the magnetospeed with a dozen or more rifles and the drops never matched up at EVERY distance. From my experience AB gets you in the ballpark. Real life is a different story.

 

[Intell]

Thanks for the reply. Mine does the same with a 308 and a 6.5 creedmoor, both canted bases. It will run true to 500-600 yd's then I'll be shooting low beyond that. Then when I true velocity it's okay on out to 800-1000, but when I shoot close range again 200-500 I'm over shooting everything. Targets are sub moa plates. I guess the nut behind the trigger is a possibility also. I've tested the scopes at 100 dialing up and they seem to track true.

 

[CharlieNC]

Try it again on a few more days and see what you get. Parallax, Sun light, wind, shooter. Etc etc affect the answer you get so you need to determine a good average at multiple distances in order to achieve a good ballistic calibration. Doing this, I've always developed an accurate truing which subsequently worked extremely well. There will always be an unusual result which is difficult to explain, and you certainly don't want to use it to calibrate the ballistics.