You're presuming your measured drops based at various yardages run backwards through a ballistics program provides you with a MV as accurate as my measured velocity over triplicate chronographs. This involves at least three immediate sources of potential error.
1) Shooter error at long ranges. You may be dead nutz on or you may not be. Could be a 12:00 or 6:00 wind. At long ranges like 1000 yds, if you're not including coriolis drift for an eastward or westward shot, you could automatically have several inches of error built into your measurement. An error in your drops for these or any other reasons will lead to an errant MV from a ballistics program, even if the BC of your bullet is exactly correct.
2) Your bullet BC out of your rifle may not be the same as it was out of Bryan Litz's rifle. There's a scholarly fellow that occasionally posts on this Forum that does a lot of research for a living, and he's documented significant differences in BC from the same bullet out of different rifles. First name is Michael. Seems he does some work under contract for the military.
3) Error in the ballistic program. No all ballistic programs are built equally. Dunno which one you use. Some don't even incorporate coriolis.
So you can fudge BC and MV with any ballistics program and come up with a match for your measured drops at any single yardage. Doesn't mean the BC and MV are accurate. Just means you tweaked two input variables in a mathematical equation to got the drops you measured. Take faulty (yours may be perfect every time and good for you) MV and BC values and re-apply them with a ballistics program under different environmental conditions, and bad data input will result in bad data output.
I contend measured MV from a decent chronograph, properly operated, with a proof channel to detect bad velocity data, is a more accurate method of determining MV than back calculating MV through a ballistics program based on measured drops. If you want to disagree, that's fine and your option.
On a second topic, there's a good reason Ken Oehler designed the proof channel into his 35P chronograph. He learned early on that every chronograph, even those of his own manufacture, will occasionally record and provide a faulty velocity. The proof channel or a second chronograph run in tandem, allows these faulty data to be identified and discarded. I experienced this problem and learned this lesson myself, as soon as I started running two chronographs in duplicate. Since I use chronographs to identify loads with acceptable low ES and SD during my load development, it's important to me to be able to identify ES and SD accurately. Otherwise I throw out a potentially good load, based on a faulty chronograph velocity, wasting time and money in the process. This is the primary reason I say anyone that makes claims about the quality, accuracy, and precision of their chronograph based solely on the singular velocity data their chronograph records, is operating semi-blind, and possibly, without knowing it. And FEENIX, if you don't accept this premise, or care about it, good for you. It is important to me, the way I use my chronographs. You dismissing the significance doesn't negate the facts. Just means it's not important to you, or for whatever other reason, you could care less.
gun)lightbulb
