For ELR what constitutes a good zero?

[Greyfox]

Pertaining to my LR rifles,,while I may set my scopes mechanical zero at 100 yards, and spot check at that distance, a habit I developed years ago is calibrate/zero my load during a "wind free" or accurately compensated condition at 200 yards. Perhaps I'm overly analytical, but any 100 yard error(ie.parallax) is magnified 10X at 1000 yards. With a precise 200 yard test, any potential error is reduced to 5X… I'm usually testing both the rifle and myself. However, I do expect my 100 yard zero and 200 yard group to coincide, and, will confirm at my furthest intended range.

 

[Bravo 4]

I completely agree. I think that`s true with any bullet. I shoot only Bergers, and it seems to me that the BCs are fairly accurate as per Bergers numbers. Scope mechanics, and tracking are another story, as scope quality goes up so does turret precision

Yeah advertised BC from any manufacturer is just a good place to start. Too many variables can affect it to nail down a true number that can simply be put into a ballistic app. Even then, BC is a dynamic number and not static. From short to moderate range it can be that simple, plug in the BC and adjust MV and things will line up fairly well. However we are talking ELR and it just isn't that simple.
Rifles scope adjustment can/will change over time. I have had 1 scope that I trust because it has not let me down…yet! From my testing it appeared to track 100%, always returns to zero and doesn't lose it. I will admit that I have not checked it in a few years. Really don't want to, maybe because ignorance is bliss. Like my wife, the most reliable person I know. If I felt the need to keep checking up on her she'd be gone!

 

[waveslayer]

For simplicity you have to true up any ballistics calculator, kestrel etc... unless you just use your real life data (DOPE).

600-800 True the velocity. No matter how good your chrono I'd

100 yards plus true the BC.

The bullet never lies