Eliminating Parallax

[Bart B.]

When shot from most stable positions allowed......

Rimfire from 50 to 100 yards, centerfire from 200 to 1000.

"Went to call." means bullets strike the target where the sights were aligned to when the round fired. A tolerance of half the system test group size is considered. If your stuff tests no worse than half MOA at target range, shots should strike within 1/4 MOA of call; atmospheric conditions allowing, naturally. A good marksman can hold point of aim inside a half MOA.

Everyone whose shot 20 record shots slung up prone shooting rimfire ammo at 50 yards all inside 1 MOA scoring Xes with metallic sights all say target, front and rear sight centers must be on one axis (no parallax ((or misalignment))) with either one) to do that.

Same for centerfire from 200 to 1000 yards with at least 2/3rds of 15 or 20 with a few deep in the 10 ring due to environment conditions

[JohnKSa]

Maybe someone can explain why my shots aimed with aperture front and rear sights having a 29 to 38 inch radius never pointed the barrel such that bullets went to call (for rifle-ammo accuracy) at ranges from 50 to 1000 yards unless their centers were all on the same visual axis from eye to bullseye target.

Because properly aligning iron sights involves putting the front sight/rear sight/target in a line and the only way to see to do that is if your eye is also in the same line.

That said, the article you brought up asserts (and backs up the assertion with real-world testing and scientific explanations) that well-designed aperture sights are forgiving of minor misalignment of the rear sight and the eye.

[Bart B.]

Originally Posted by JohnKSa

That said, the article you brought up asserts (and backs up the assertion with real-world testing and scientific explanations) that well-designed aperture sights are forgiving of minor misalignment of the rear sight and the eye.

Not when the test groups are greater than MOA without tests with a scope to establish what the rifle can do with the ammo and no plots of call versus shot hole to show errors caused by parallax errors.

Don't forget about the other axis whose angle and direction from the two sights axis doesn't change.

[JohnKSa]

I'm ok with just the first part of my explanation, but since you brought up the article, I thought it made sense to at least give its contents a nod.

So:

"Because properly aligning iron sights involves putting the front sight/rear sight/target in a line and the only way to see to do that is if your eye is also in the same line."