How Important Is Side Parallax for 0-600 Yard Hunting?

[lancetkenyon]

I agree with you on that Lancekenyon, but do you think you could put the Steiner 2-10x50 without a parallax adjustment on your rifle and still connect confidently out to 600 yards?

Yes, I do, if your shooting technique and positional awareness/consistent cheek weld are near perfect. But I would still prefer side parallax adjustment, even for 600 and under on a scope with less magnification if possible. It seems like from 50 to 600 yards, there is more parallax correction needed than from 600 to infinity. So I think it might be even more important in that yardage range. Especially if multiple shooters could be using the rifle. And an "Ajustable objective" on the front bell is still adjusting. Just on the front vs the side.

I missed the part of shooting a 14" group at 600 yards. Honestly, if that is the case, you currently have no business shooting at game at 600 yards. That is a 2.3MOA group. Or, a 300-350 yard max distance on deer-sized game. And that probably doesn't include varying environmental factors either.

An 8" group is the max in my opinion for hunting. Whether you shoot the 8" at 200 or 1200, that is the determining factor on where your distance limit should be adhered to.

I have plans to build a true short/lightweight 600 yard rifle, probably in 6.5x47L.
The scopes I have been looking at are:
S&B PMII 1-8×24 Short Dot Dual CC (no parallax adjust, set for 100yds)
March F 1-10×24 (side parallax)
If the March Compact 1.5-15×42 would be released in a FFP, that would be in the running too. Even if it went to a 1.9-15×42 (most March FFP are 8x erectors).

 

[Bravo 4]

Correct Sobrbiker. I listened to a podcast a few months ago where a Leupold Tech was talking about how to calculate max parallax error. I'll see if I can find it. Surprised me that there were some things that were opposite of what I previously thought.

Divide obj lens diameter by 2, multiply that by the difference in range between where your parallax is set and the target, divide by the range your parallax is set to, this will give you a solution in mm and to convert to inches multiply by .03937 (or however you want to round that number).
example:
50mm scope obj
parallax set @ 100 yards
target @ 900 yards
difference in yards of parallax setting to target of 800 yards

50/2= 25
25x800= 20000
20000/100= 200mm
200mm x .03937= basically 8" max PA


or make you a chart with https://www.lelandwest.com/parallax-error-calculator.cfm


added: will I take this as gospel...No...but can give you an idea.

 

[cajun]

Well you can just leave it set at 100 for most of your hunting and only use it if you have time on longer shots. It may not be necessary but nice to have.

 

[Bravo 4]

If just referencing parallax I can agree with set & forgot to a point, but I would prefer to have it set for further range. Play with that calculator and you will see why. As an example here are two screenshots (pics below) of the potential effects of 100 yard parallax setting compared to 400 yards. If set for 400 then it only has minor effect all the way out to 1000+ yards. The real problem with taking long range shots at this point could be target image being blurry and need to be focused.
If I have time I will definitely adjust parallax out as it is just one more thing I can control.

 

[CrankyYankee]

Excellent Bravo 4, thank you.

Lancetkenyon, you are correct. The smaller the game, the closer my max range will be. My limits, I know. Reckless, I am not. (Sorry... was just watching Yoda).

 

[WildRose]

Parallax adjustment is critical for long range shooting. Scopes without a parallax adjustment are set at the factory for 100 yards. Anything closer or beyond 100 yards your eye has to be perfectly centered to make a good shot. Adjustable parallax scopes internally adjust the parallax so that at the given range it;s adjusted to allows for a slight off center condition of the eye to not make a difference in the bullet impact. Notice I said slight off center. One cannot get sloppy and expect the parallax adjustment to compensate for their carelessness. If you don't have time to adjust or forget to adjust for the distance as long as your eyeball is perfectly centered it won't make a difference. The more the range varies the less off center eyeball is allowed before the bullet is going to go it's way, not the way you wanted it to go. Parallax is critical at all ranges. Eye centered in the scope eyepiece is critical at all ranges. 1/64th of an inch off center can send your bullet out to LA LA Land at 600 yards.

With good scopes that's really not an issue. You can put the crosshairs on a target and move your eye around in the eyebox and see the crosshairs are not moving from POA.

Cheaper scopes that is an issue.

 

[WildRose]

If just referencing parallax I can agree with set & forgot to a point, but I would prefer to have it set for further range. Play with that calculator and you will see why. As an example here are two screenshots (pics below) of the potential effects of 100 yard parallax setting compared to 400 yards. If set for 400 then it only has minor effect all the way out to 1000+ yards. The real problem with taking long range shots at this point could be target image being blurry and need to be focused.
If I have time I will definitely adjust parallax out as it is just one more thing I can control.
View attachment 335438View attachment 335439

That is why mine stay set for 350-400 yards.

If I have to make a quick shot up close that's a very small error, the reverse though can induce a very large error.

 

[Teri Anne]

With good scopes that's really not an issue. You can put the crosshairs on a target and move your eye around in the eyebox and see the crosshairs are not moving from POA.

Cheaper scopes that is an issue.

While this is true for tactical scopes or scopes with parallax adjustment try looking through your fixed parallax scope either at shorter distances th 100 yrs or longer distances. You will see the point of impact move sometimes substantially or if you have your scope that has adjustable parallax set to the wrong distance.

Everything needs to work together to get the bullet on the point of impact. If all are the same for each shot, the bullet will go into the same hole. Parallax is simply one of the many factors that cause hits, misses or flyers.

 

[WildRose]

While this is true for tactical scopes or scopes with parallax adjustment try looking through your fixed parallax scope either at shorter distances th 100 yrs or longer distances. You will see the point of impact move sometimes substantially or if you have your scope that has adjustable parallax set to the wrong distance.

Everything needs to work together to get the bullet on the point of impact. If all are the same for each shot, the bullet will go into the same hole. Parallax is simply one of the many factors that cause hits, misses or flyers.

Even with quality FP scopes you have a good forgiving eyebox. It's easy to test by putting it on a target an moving your eye position to see if there's a shift of the crosshairs.

I have some fixed parallax Trijicon and Zeiss and have found this to be completely true with them whereas with older and lower quality FP scopes it is a problem.

 

[Teri Anne]

Even with quality FP scopes you have a good forgiving eyebox. It's easy to test by putting it on a target an moving your eye position to see if there's a shift of the crosshairs.

I have some fixed parallax Trijicon and Zeiss and have found this to be completely true with them whereas with older and lower quality FP scopes it is a problem.

There is a tendency for people to forget the basics and not pay attention to parallax. I read all about flyers in posts here, all blaming everything but the eye behind the scope which is the cause of 95% or more of the flyers.

 

[WildRose]

There is a tendency for people to forget the basics and not pay attention to parallax. I read all about flyers in posts here, all blaming everything but the eye behind the scope which is the cause of 95% or more of the flyers.

I've never seen anything to suggest that is true.

 

[Teri Anne]

I've never seen anything to suggest that is true.

Try being a firearms instructor and you will find it rampant these days when everyone doesn't believe anything especially men who think they know it all.

 

[WildRose]

Try being a firearms instructor and you will find it rampant these days when everyone doesn't believe anything especially men who think they know it all.

I've been a civilian, police, and military instructor since 1977.

 

[Hugnot]

Practical applications -- "look it's a rattle snake 8 feet away to your left" >> carefully back away, verify safety of shot, go down from 14X to 4.5X, adjust focus/parallax to shortest range, center eye in scope, aim about 1.25"over creature's head, shoot >> happens now & then. The previous shot might have been at a leisurely 400 yards. Side focus helps. On that trip, I shot, 50-60 prairie dogs, 1 rock chuck, 1 coyote, & 1 rattle snake within 4 hours from ranges up to 400 plus on quart size milk carton targets, to 12 feet on golf ball size targets & used focus/parallax continually. Avoid the damp looking grassy areas with the red winged black birds. 4.5-14X works just fine when circumstances vary.

I have a old, fixed parallax, Zeiss 3-9X40 Conquest & it has very little <--> movement with changes in eye position at 50 yards or so & almost none at 100.