Question on ballistic app data inputs

[Sticks]

Thanks Sticks. Is your barrel a 1:8 twist also?

Yes it is

Barrels can and do differ, I have 1 18"-er that's fast (the Amax and SST's run 2510 in mine) but the Hdy Black runs slower, I don't know why but that's what it is.
So the chrono is really worth it to you. Especially if you want to reload.
Just a thought.

Best advice here. A simple Chrono will run you $99 or so, then you will have accurate info on what your rifle does with each ammo. Extrapolating data from other users with the same barrel length, twist, and hopefully the same mfg as yours will get you close, then you can dial it in shooting long range (500y or more).