How much will a 300 yard parallax setting effect a 100 yard target?

Just noticed the HD5 With Rapid Z 600 has a 300 yard parallax setting. I know it won't be off enough to matter on game animals but how much will it effect the ability to shoot one hole 100 yard groups?

Does a 300 yard parallax appeal to anyone who shoots longer distance? I got this scope for it's versatility just in case I ever get a chance to hunt a longer distance, but most of my shots will be within 100 yards.

Back in the 1970's Robert Klienguenther guaranteed his rifles to shoot 1/2" groups at 100 yards. In his manual he suggested people pull back from the ocular far enough that there was more black than light in the scope. The you center the crosshairs in the small circle. I guess it works. That's how I did it and accomplished 1/2" groups.

Lock the gun on a sandbag as best you can w/the crosshairs on a small point of aim. Move your eye around the ocular and see if the croshairs move off point. I bet they do only a tiny amount...if at all. That would be the possible error.

If your eye is perfectly centered in the scope, then none.

Find a repeatable position that is in the right place and you are all set.

From a Leupold owners manual

Quote

UNDERSTANDING PARALLAX
Parallax is the apparent movement of the target relative to the
reticle when you move your eye away from the center point of the

eyepiece. It occurs when the image of the target does not fall on
the same optical plane as the reticle. This can cause a small shift
in the point of aim. Maximum parallax occurs when your eye is
at the very edge of the exit pupil (Even in this unlikely event, our
4x hunting scope focused for 150 yards has a maximum error of
only 8/10ths of an inch at 500 yards). At short distances, effects
of parallax do not affect accuracy (using the same 4x scope at 100
yards, the maximum error is less than 2/10ths of an inch ). It is
also good to remember that, as long as you are sighting straight
through the middle of the scope, or close to it, parallax will have
very little effect on accuracy

I doubt if a Zeiss is much different.

Originally Posted by JMR40

From a Leupold owners manual

Quote

UNDERSTANDING PARALLAX
Parallax is the apparent movement of the target relative to the
reticle when you move your eye away from the center point of the

eyepiece. It occurs when the image of the target does not fall on
the same optical plane as the reticle. This can cause a small shift
in the point of aim. Maximum parallax occurs when your eye is
at the very edge of the exit pupil (Even in this unlikely event, our
4x hunting scope focused for 150 yards has a maximum error of
only 8/10ths of an inch at 500 yards). At short distances, effects
of parallax do not affect accuracy (using the same 4x scope at 100
yards, the maximum error is less than 2/10ths of an inch ). It is
also good to remember that, as long as you are sighting straight
through the middle of the scope, or close to it, parallax will have
very little effect on accuracy

I doubt if a Zeiss is much different.

So, if that holds true then since the Zeiss is set to 300 yards instead of 150 yards, the max would be a little under 1/2" at 100 yards. Certainly enough to cause a larger group at 100 but that's the max and everything would depend on the shooter's repeatable position.

Acually it can be more than that. Or even alot more. That's because the 4X Leupold used in this case has a long depth of focus. But a 10X scope has alot less, so it's "parallax error" could be a quite a bit more.
The best examples I've seen are from the Leupold 6X42 on my .25-284 and the 7.5X AO scope I have on my .280.
The .25-284, with the scope set with almost no parallax at 300 yds. regularly produces 2-2.5 inch groups at 300 yds. But at 100 yds., the groups run about 1.2 inches.
The 7.5X AO however has a differently story. With it set almost parrallx free at 100 yds., the .280 would shoot .5-.6 MOA groups. But at 300 yds. w/o removing the parallax, it would shoot 5-7 inch groups. E

Originally Posted by R_H_Clark

Does a 300 yard parallax appeal to anyone who shoots longer distance? I got this scope for it's versatility just in case I ever get a chance to hunt a longer distance, but most of my shots will be within 100 yards.

It does to me.

The Rapid-Z 600 reticle is designed/optimized for longer ranges (i.e., 300 - 600 yards) so it makes perfect sense the parallax zero be set at 300 yards in a fixed parallax scope.

Of course it's less suitable for precise target or load development work at 100 yards. Either use another scope or be very careful about consistent eye placement for "close in work". As others have pointed out, you can measure the amount of parallax by keeping the gun fixed and moving your eye placement side-to-side, up-down. With this scope I see about 1" peak-to-peak parallax at 100 yards.

You won't shoot many 5 shot 100 yard groups for your wallet with this scope, but it's really good from 250 to 600 yards AND it won't cause a miss/poor shot on a big game animal at close range.

Zeiss got it right.