SC
This whole ballistics discussion and interest therein boils down to why do I shoot and hunt. Some like the arcane and mystical pursuit of unusual solutions to problems. For them the discussion of SD reduction rates, impact velocities, atmospherics and Coriolis effect are all germane and endlessly interesting. This is particularly important to those that shoot and/or hunt at long range.
For 95% of hunters that shoot all their game under 300 yards and 90% of that at 150 or less; they shoot to get game and eat wild meat. For them simple is the right solution. Take a big enough gun with a heavy enough, well constructed bullets, put them in the right spot and that is all they care or need to know about ballistics.
If you want guys to engage on this discussion my bet is that the Long Range Hunting Forum would have many more interested takers.
https://www.longrangehunting.com/forums/
By the way, shoot that same 6.5 with a 160 grain bullet and you won't have to worry about SD reduction rate.