PRACTICAL effects of parallax 10-200 yds?

[NWPilgrim]

I've searched the web and forums for specific information on the effects of parallax in the field and informal target shooting, not precision target shooting. Also searched at rimfirecentral forums as I am mostly interested in this for shooting .22LR. I am asking here on M4C because there seem to be a lot of guys shooting target and steel centerfire like .223 from 30-600 yds using non-AO scopes.

Specific results I found were only from tests of extreme conditions (moving eye to very edge of field of view and compare to center view). In the extreme case you can see 1" - 2" difference in point of impact at just 50-100yd changes. Some observe that the eye naturally aligns itself to the center so parallax would be minimal in practice.

My situation is that I have "sporter" rifles like 10/22 and M&P 15-22, shooting standard velocity CCI and Agulia, with a centerfire scope of Leupold VX1 2-7x33 with 150 yds fixed parallax. I currently have only shot it with targets out to 50 yds and get about 1 1/4" 10-shot groups. I am interested in trying out targets at 100 yds and maybe 200 yds. My only concern really with target accuracy is to determine the accuracy of a brand and style of ammo in different firearms; and is parallax adding significant variability under these conditions or is it insignificant? The selection and availability of quality rimfire scopes is much more limited than centerfire.

This lead to wondering the effect of parallax in general. If not engaging in precision/benchrest/long range varmint shooting, are Adjustable Objective/Side Focus scopes needed at all? Has anyone compared a 150 yd fixed parallax scope to a 50 yd scope at 10 yds, 30 yds, 50 yds, 100 yds and found how much difference there is in reality, not just theory? Are we talking 1/4" differences?

Some of the factors that seem to be involved from what I have read so far:
* More magnification exaggerates the effect. 10x and below the parallax difference may be insignificant?
* Does the eye mostly align naturally with center of eyepiece?
* Larger objective lens (e.g., 50mm vs 28mm) also increases the difference?

Guys that shoot rimfire steel, do you use AO scopes or rimfire scopes or low power variable centerfire? Is parallax a concern at all for shooting small steel from 30-200 yds?

[SomeOtherGuy]

Some of the factors that seem to be involved from what I have read so far:
* More magnification exaggerates the effect. 10x and below the parallax difference may be insignificant?
* Does the eye mostly align naturally with center of eyepiece?
* Larger objective lens (e.g., 50mm vs 28mm) also increases the difference?

All correct AFAIK, based on both personal real-world experience and what I've read. Eye alignment is a bit of an issue of shooter skill/preference but it should be easy to teach yourself and practice. As you've probably read, if you can always keep your eye dead center in the scope, the parallax is irrelevant. Parallax itself (not focus) only matters when your eye is off center. But it's hard to keep your eye absolutely perfectly centered.

This lead to wondering the effect of parallax in general. If not engaging in precision/benchrest/long range varmint shooting, are Adjustable Objective/Side Focus scopes needed at all? Has anyone compared a 150 yd fixed parallax scope to a 50 yd scope at 10 yds, 30 yds, 50 yds, 100 yds and found how much difference there is in reality, not just theory? Are we talking 1/4" differences?

Guys that shoot rimfire steel, do you use AO scopes or rimfire scopes or low power variable centerfire? Is parallax a concern at all for shooting small steel from 30-200 yds?

From 25 to 300 yards, if the target is in focus at the selected magnification, parallax is likely to be insignificant except for purposes of benchrest or other serious and precise competition. Even for serious competition, parallax is trivial up to 6x with most scopes, and only a small issue from 6-9x. At 10x it is becoming significant, and above 10x you generally want adjustable parallax or to stay close to the target distance of the scope's fixed parallax.

There is a reason that all LPVs and most 3-9x hunting scopes have fixed parallax, along with a large share of the 2-10x scopes. It works fine for practical use. Moreover, I have noticed that fixed parallax scopes in the 3-9x or 2.5-10x magnification range often have a wider range of distance where targets are in focus, compared to a same magnification adjustable scope set at the 100 yard parallax setting. I don't know exactly why this would be, but it seems consistent across brands.

Another benefit of fixed parallax is that it means one less lens in the system when compared to a side focus, which not only reduces cost and weight but helps light transmission and clarity. (Adjustable objective scopes would have the same number of total lenses as a fixed parallax scope. They also aren't common at higher quality levels and aren't convenient to use.)

Tip: focus and parallax are not the same thing. In really good scopes you should have zero parallax when the target is perfectly focused, but this is not guaranteed, and you can't take this as a given. This is most likely to be an issue if you have the reticle focus (diopter) far from its center position, due to your eyesight. You should test this, by focusing on the target and then moving your eye around to see if there is any apparent movement between target and reticle.

For airgun shooters and anyone else trying to be precise at less than 25 yards, parallax can be a big issue and adjustable parallax is probably important. Likewise if you're shooting at 600+ yards, or if you're doing benchrest or F-class at any distance other than 100 yards.

[1168]

I’m not quite as knowledgeable about target type riflescopes as the poster above, however I do own a Leopold 2-7, and several other hunting scopes. It has been used on a .22LR semiauto and a .22WMR out to 100 yards without any issue. I also had it mounted on a 5.56 AR for a few years that has been shot from 4yards out to ~300 yards, with no issue. It was on a .35Rem levergun at one point also, only shot out to 100 or so yards. It doesn’t have a huge round count, but I have not experienced any problems with focus or parallax. I zero it, and at any practical range, I am happy, whether shooting at squirrels or deer.

Most of my scopes are modest in magnification (I live in the Southeast), and have fixed parallax. The one scope I own that has adjustible parallax, on the other hand, seems to be very sensitive. Its a 14.5 power VX4, and if I don’t have it dialed just right, my POI wanders. This one has been used from 100-500 meters on a .22-250. Shooter error, for sure, but I have no problem with LPVO’s with fixed parallax at the same ranges.

My favorite hunting and general use, medium magnification, scopes that I own are a 2-7x Leupold and a 2.5-10x Zeiss. They keep it simple. For me, I’ve concluded that adjustable parallax is unneeded. I‘m not into benchrest.

Hope this helps.

[GH41]

I agree with SomeOtherGuy and will add this... Before the internet 99% of us got by fine without knowing what parallax was!