I didn’t specify - the 5, 10, 15” I shared above is from a 100 yard zero.
ETA: that’s coming from experience loading 450 Bushmaster, 458 Socom, 45-70, 450 Marlin, 45-110, 454 Casull, 44mag, 445 super mag, 444 marlin, throwing similar BC bullets at similar speeds.
Not knowing your velocity (which seems like a 20+ year reloader would have), but knowing the 450 loses about 30fps per inch, and reading the Hodgdon data for your bullet and load - 37.6grn @ 2036fps from a 24” barrel, less 8 x 30 = 240fps reduced velocity from a 16” Ruger American, I’d expect about 1800fps.... so putting a .215G1 and 1800fps into the Hornady calculator:
150yrds = 4.62”
175yrds = 8.72”
200yrds = 14.13”
Add another 100fps, leave station at 1900, 150 becomes 4.03” and 200 becomes 12.47”. Still close enough my estimate would have had you on target. Lose 100fps instead and launch at 1700, you’d be 5.29”, 9.95”, 16.05” at 150, 175, and 200... see a pattern here?
So spitballing 5, 10, and 15, after 30yrs myself of shooting punkin’ chunkers, sure would have had you close enough for you to reach out and be respectably close on target at 150, 175, and 200 yards. Really isn’t that complicated.