Parallax adjustment

[Steve Donlon]

I did not have any problem at 500 and 800 yards but at 1000 yards my eyes where the problem. But when I stopped looking at the big picture and just concentrated on a very small point on the target I was back in the game. I think using the new Lapua 144gr. bullets also where factor. At 1000 yards they seemed to shine. Along with all the other parts of reloading. It all came together after reading what everyone had to say about parallax and where to focus my attention.

 

[alf]

Just some observations.....

Anyone else ever notice on some scopes, that the best clarity and no parallax don't always jibe? Meaning you dial out the parallax, but there's a slight loss of clarity, so you focus for perfect clarity on the target, but then there's a bit of parallax?

I switched over to Vortex Viper HD's in 5-25x50 FFP for my prairie dog rifles, & found what was mentioned earlier. At/around/beyond 1K, the side focus is maxed out, & could use just a hair more adjustment. For best clarity, I need to tweak the eyepiece, coming to a compromise between clarity & a sharp reticle. Talking to Vortex, they seem to be more concerned about the numbers on the side focus matching exact yardages, than the LR aspect of good/perfect parallax.

I did buy a couple three Athlon Ares 4.5-27x50 scopes that don't have those issues, but are just behind the Viper HD's in overall clarity & brightness.

My Nightforce NXS 5.5-22x50's have none of these issues, but of course are 2-3 times the $.

 

[Rank Amateur]

I know a little about a lot of things, and a lot about very few. Gunsmithing, external and internal ballistics, optics, metrology, and all the minutiae of loading and tuning are things that fall into the former category. I remain grateful for this forum which provides access to some of the top experts in all of those fields. I learn from and benefit from all of you. Thanks for your contributions.

 

[jelenko]

Just some observations.....

Anyone else ever notice on some scopes, that the best clarity and no parallax don't always jibe? Meaning you dial out the parallax, but there's a slight loss of clarity, so you focus for perfect clarity on the target, but then there's a bit of parallax?

I switched over to Vortex Viper HD's in 5-25x50 FFP for my prairie dog rifles, & found what was mentioned earlier. At/around/beyond 1K, the side focus is maxed out, & could use just a hair more adjustment. For best clarity, I need to tweak the eyepiece, coming to a compromise between clarity & a sharp reticle. Talking to Vortex, they seem to be more concerned about the numbers on the side focus matching exact yardages, than the LR aspect of good/perfect parallax.

I did buy a couple three Athlon Ares 4.5-27x50 scopes that don't have those issues, but are just behind the Viper HD's in overall clarity & brightness.

My Nightforce NXS 5.5-22x50's have none of these issues, but of course are 2-3 times the $.

I've heard others mention this also.

I always go with the clearest sight picture. The fuzzier it gets the longer it takes me to be comfortable to take the shot.
ALSO. If the objective is focused close to the actual distance to the target, the error from parallax is tiny. [I don't compete in benchrest].

The formula for max parallax error is PE[max] = 1/2 D X [ R - P ] /P
D= Diameter of the objective lens; R = distance to the object; P = distance at which the objective is focused.

First, that's the max error when you're eye is as far to one side as possible but still be able to see the image
As you can see, if the distance to the target and the distance at which the objective is focused, [R - P] becomes small and then, you're dividing my the distance at which the objective is focused.

For example, at 500 yards with a 50mm objective, the objective focused at 525 and the distance to the target is 500,

PE[max] = 1.2 X 50mm X [ 500 - 525]/525 = 1.2mm = .05inch. Or .01 MOA.

 

[6MMsteve]

First thing I do is set diopter for clean crisp CH then I'm done which takes a few tries bobbing and weaving

 

[Steve Donlon]

First thing I do is set diopter for clean crisp CH then I'm done which takes a few tries bobbing and weaving

That was a part I did not do, the bobbing and weaving then spent more time tuning.

 

[6MMsteve]

That was a part I did not do, the bobbing and weaving then spent more time tuning.

Tuning can be kinda hit n miss if CH are moving floating I think

 

[ELR LVR]

Just some observations.....
Talking to Vortex, they seem to be more concerned about the numbers on the side focus matching exact yardages, than the LR aspect of good/perfect parallax.

Yes thats exactly the problem we're having with the $3k and above scopes
SO while I understand it would be difficult to place markings that coincide perfectly with the yardage adjusted for past 1000 yds
We still want that additional range of adjustment, regardless of any markings lining up with the yardage.
They are NOT GETTING IT!
For the money, we should get what a freaking Simmons can do in that dept. lol