Talk to me about ranging in dark conditions

[Bramezy]

Hey all,
I would really prefer some actual first hand experience here, not some you heard this or that.
Apparently I'm having issues ranging in the darker conditions. I get a nice and clear target but its at a closer distance than when its lighter out.
Is this a common thing? Is this a lower quality of glass thing?
I am using an Athlon Argos Gen2 6-24.
I feel like I need to do my own test here of a known distance in dark conditions and light conditions and see what I get. I wasn't aware of any issues like this but I was also fighting accuracy issues all year. Now those are gone, I'm seeing I'm having some ranging issues. At the sight in range I felt like all of my ranges checked out and were spot on.
So, does anyone have concrete first hand experience with this and what was your findings and solution? Was there a certain type of scope, or feature of a scope that helped this?
Im not able to just start buying $500-1500 scopes to test. Its hard enough to get another scope, especially this time of year. Before I make that jump if I have to, I would love some real world input.
Appreciate your time.

 

[thomasair]

It’s normal. There are dual pointers made with a pin for light and a pin for dark. You are correct that you should just do your own tests and chart your results. Scopes are all different.

Mike

 

[Cloud9AG]

What Mike said.

 

[B_y_r_o_n]

Take a look at post #3 in this thread. It should make it clear why you are seeing a difference in ranges.

 

[Bramezy]

Take a look at post #3 in this thread. It should make it clear why you are seeing a difference in ranges.

Thanks. So seems like yes the different conditions present different affects on the target. Would explain my issues lately. I will have to spend some more time gathering data. Thanks

 

[Cloud9AG]

Take a look at post #3 in this thread. It should make it clear why you are seeing a difference in ranges.

I'm not sure that that post applies to using a scope; it talks almost exclusively about front sights and the apparent size of the bull with open sights. The only thing out of that thread that I believe applies is the effect light has on your pupil size and the resulting impacts on your ability to determine when the target is in focus using the parallax knob.
Like @thomasair said above, dark and bright conditions affect your vision and your ability to discern when a target is in "focus" and thereby determine it's distance from you. I have experienced 3 different situations shooting Field Target with Sightron and Kahles scopes:

1. Overall bright day - I find ranging easy with a scope on days like this. I shoot WFTF, and using 50x to range I can easily pick out the fuzz on the string or minor paint chip at 55 yards. This is my most accurate ranging condition.
2. Bright day with sun above and behind me - On these days, I wish I used an eyecup to keep the light out of the eyepiece. I use a Tubb shooting hat in these conditions to keep out as much light as possible. Light that comes into your eye from the side or reflecting off the eyepiece affects my ability to see the target clearly and range accurately with the parallax. The picture never really comes into "focus" due to the extraneous light from the sun behind me bouncing into my eye.
3. Heavy overcast day or Targets in dark - These are the most challenging targets for everyone. I believe the reasons are that our eyes do not discern details well in darker conditions, and that is counterproductive to trying to see details and determine ranges to targets. I find that at high powers (and even at 40x sometimes), my eyes struggle to get enough light through the scope to let me determine details on the target and when it is in "focus". When this happens, I often switch to bracketing to help me verify the distance to the target.

If you shoot Hunter (which I used to do), all of the above apply to targets out to 40-ish yards, and then after that I use bracketing on a known object (target support brick, target support 2x8 board, 1.5" KZ past 45 yards) to verify the range to the target. Even in the best light and with a very good scope, I cannot accurately range targets past 40yards at 16x magnification.

My advice is practice in these conditions, develop your range modifiers for conditions other than your original parallax wheel setup conditions, and then use that additional info to help you focus on the target and determine the range (and knock it over!!).

 

[Bramezy]

I'm not sure that that post applies to using a scope; it talks almost exclusively about front sights and the apparent size of the bull with open sights. The only thing out of that thread that I believe applies is the effect light has on your pupil size and the resulting impacts on your ability to determine when the target is in focus using the parallax knob.
Like @thomasair said above, dark and bright conditions affect your vision and your ability to discern when a target is in "focus" and thereby determine it's distance from you. I have experienced 3 different situations shooting Field Target with Sightron and Kahles scopes:

1. Overall bright day - I find ranging easy with a scope on days like this. I shoot WFTF, and using 50x to range I can easily pick out the fuzz on the string or minor paint chip at 55 yards. This is my most accurate ranging condition.
2. Bright day with sun above and behind me - On these days, I wish I used an eyecup to keep the light out of the eyepiece. I use a Tubb shooting hat in these conditions to keep out as much light as possible. Light that comes into your eye from the side or reflecting off the eyepiece affects my ability to see the target clearly and range accurately with the parallax. The picture never really comes into "focus" due to the extraneous light from the sun behind me bouncing into my eye.
3. Heavy overcast day or Targets in dark - These are the most challenging targets for everyone. I believe the reasons are that our eyes do not discern details well in darker conditions, and that is counterproductive to trying to see details and determine ranges to targets. I find that at high powers (and even at 40x sometimes), my eyes struggle to get enough light through the scope to let me determine details on the target and when it is in "focus". When this happens, I often switch to bracketing to help me verify the distance to the target.

If you shoot Hunter (which I used to do), all of the above apply to targets out to 40-ish yards, and then after that I use bracketing on a known object (target support brick, target support 2x8 board, 1.5" KZ past 45 yards) to verify the range to the target. Even in the best light and with a very good scope, I cannot accurately range targets past 40yards at 16x magnification.

My advice is practice in these conditions, develop your range modifiers for conditions other than your original parallax wheel setup conditions, and then use that additional info to help you focus on the target and determine the range (and knock it over!!).

Thank you very much! Very informative.

 

[Bladesx]

I think I have this right been years, sun up sights down , sun down sights up. scope or irons. If you have ever shot a day long match or say later in the year when the sun sinks rapidly you wiil notice a tendancy to track the sun, or get pulled by it, which ever you prefer. Plenty of us have lost a point or 2 when the sun dives behind a cloud and then pops back out. or late afternoon in the fall when the sun's arc gets it low in the sky you will tend to shoot off to that side if crosswise to it. glasses or contact lens, refract the light a bit as well gives you a tail on an object. We have natural tendency to be attracted to light.

 

[B_y_r_o_n]

Thanks. So seems like yes the different conditions present different affects on the target. Would explain my issues lately. I will have to spend some more time gathering data. Thanks

That is what I wanted you to pick up on. It's all about gathering more data.

 

[davecole]

If you are utilizing a sun shade you might remove it and see if it improves the brightness down range.
I used to have one on my scopes just because it came with one. But I found not using it, unless the sun's glare was in front of me, made a difference in the brightness of the lane. I carry mine with me, I just don't put it on unless I need it. You may also want to consider a flash kill as opposed to a sun shade. Athlon does not offer one TMK but there are some on Amazon that claim to be compatible. If it doesn't fit, Amazon has the easiest return process I'm aware of.
And as Jeff mentioned, wear a broad brim hat so that it shades your view in the ocular. An eye cup is probably not a bad idea since it eliminates any unwanted peripheral lighting.
Best of luck!

 

[Airgunoregon]

The eyepiece reticle adjustment is very critical as well on most scopes, especially 30mm and 34mm tube scopes. I've found that a small adjustment can really change your ranging results. It's not just about making the reticle clear and bold... after that there is still a range of adjustment that you can find that helps to eliminate or exacerbate the ranging differences in different light conditions. Play with that as well and you might find a spot that will change a lot less or not at all.

Beyond that, I find that a 1" tube scope doesn't see those change hardly at all or not at all. I've really come to love and depend on the Athlon Heras 1" tube 4-20x50. It's very snappy even at 16x on the long targets. After using it for almost two seasons now, I've never seen any shifting under any conditions so far.

HERAS SPR 4-20×50 AAGR2 SFP MIL

HERAS SPR 4-20×50 AAGR2 SFP MIL PRODUCT SPECIFICATION MAGNIFICATION 4-20 OBJ. LENS DIAMETER 50 mm TUBE DIAMETER 1 in EYE RELIEF 3.6 " FOV @ 100 YDS 27.9 - 5.6 ft PARALLAX ADJUSTMENT 10 y CLICK VALUE .1 MIL LENGTH 13.3 in WEIGHT 25 oz

airgunoregon.shop

A 1" tube scope also allows one to get their scope lower to the barrel and that really lowers your room for error in range finding, by having so much less hold over for close and long shots.

I was planning to go to the Nationals, (but some of our team members had to drop out, so the drive became too much of a burden by myself), so I had installed a 30mm Athlon 6-24x56 with a lighted reticle, thinking I might need it for potentially dark targets at the Nationals.

I found the same issue as noted above when the day was cold, cloudy and rainy... my ranging was way off.. it cost me at least 5 points on day one of the SOFT Grand Prix last month. I switched back to the 1" tube 4-20x50 Heras and had no issues on day two.

 

[delooper]

Rangefinding scopes make it much easier!

I pretty much only hunt on my property, or on family property I am familiar with. So I just get used to all the distances.

 

[thomasair]

Wayne, could you explain what makes the main tube size relevant to the ocular adjustment in regard to rangefinding?

Mike

 

[Airgunoregon]

Wayne, could you explain what makes the main tube size relevant to the ocular adjustment in regard to rangefinding?

Mike

No I can't explain it, I'm only reporting back field testing of 1" tube verses 30 and 34mm tube scopes.. I'd love to see an explanation too.

 

[scotton]

A 1" tube scope also allows one to get their scope lower to the barrel and that really lowers your room for error in range finding, by having so much less hold over for close and long shots.

That's true for close shots but I think you are incorrect for long shots. Raising the scope height will make the long shots flatter while making the short shots steeper. That's why the Euro FT shooters tend to have really tall scope risers. Helps flatten the flight at long ranges with lower powered guns, since ranging errors at short range are more rare. Plus their average target distance tends to be longer than ours.

For example, my hunter setup shoots MRDs at 815 fps. A scope height of 3.28" (I know that's high, it's a Delta Wolf so that's just how it is) gives me .9 mil at 55 yards and 4.4mil at 10 yards. These are real world values confirmed on paper. If I lower the scope height an inch to 2.38 (in Strelok) I get a 1.2 mil holdover at 55 yards and a 2.4mil at 10 yards. So the long holdover increased and the short holdover decreased (by almost half!).

Another inch down (1.28) gives 1.5 mil at 55 and .4mil at 10 yards. This is all with a 30 yard zero. If I went with a lower scope height I would probably need to change to a 20 or 25 yard zero to keep from holding under, which would change the holds. The same 1.28" scope height with a 20 yard zero would give a 3mil hold at 55 yards and 1mil at 10 yards.

Oddly enough, Euro HFT tends to go with lower scope heights. I assume this is because the max target distance is 45 yards and the lack of parallax focusing makes the shorter targets more challenging, so they want the pellet flight to be flatter for more of the pellet flight and deal with a little more drop at the far end.

If I was shooting Hunter (which I'm not currently) I would probably keep the 3.28 scope height since the heavier Monster Redesigns are a little loopy at 20 fpe. If I was shooting something flatter like Heavys or Exacts, I would think about lowering the scope height a little to make the short yardage holdovers a little less extreme. When you miss a long target, there are a lot of reasons- gun, scope, ranging, wind, shooter. When you miss a short target, there's really only one reason- shooter. So I don't mind holding over (or clicking) more for the short ones if it gives me better odds at the long ones.

 

[Airgunoregon]

I am using an Athlon Argos Gen2 6-24.
I feel like I need to do my own test here of a known distance in dark conditions and light conditions and see what I get. I wasn't aware of any issues like this but I was also fighting accuracy issues all year. Now those are gone, I'm seeing I'm having some ranging issues. At the sight in range I felt like all of my ranges checked out and were spot on.
So, does anyone have concrete first hand experience with this and what was your findings and solution? Was there a certain type of scope, or feature of a scope that helped this?

scotton,
In responding to the original poster, I was offering a potential solution/compromise that seems to help me. I'm using Air Arms 10.34 in a slow poly barrel in my USFT, that is producing a high BC in Hunter class at 19.5fpe. I'm using a zero of 30 yards. My holdover is very reasonable on both long and short shots.. overall my room for error is way less than if my scope was higher than the 2.25" it is now.

So, yes you are right under the conditions you are shooting within... heavier pellets, loopier trajectory, and clicking with a high power scope not set at 16x for Hunter class.

Even in Open or WFTF class, having 3 or 4 full turns to get from zero to a 10 yard target, in my mind is leaving a lot of room for error. When I shoot WFTF PCP class, I try to still keep my scope set at about 2.5 to 2.75" so I don't have more than one full turn when clicking from my zero to a 10 yard or 55 yard shot... but that's just what works best for me.

That 1.28" example you used is looking really good to me for a Hunter class shooter... especially a new one who might have a lot of things to learn about the game.. Keep it simple, seems like a good idea to me. I wouldn't mind fudging my zero and having a 1/16" hold under at 25-30 yards to make a longer flat spot in the trajectory.. again especially for someone learning the game. Most kill zones at 25 to 30 are 3/4" to 1", so being 1/16" high is not much of an issue to me... but even without doing that, it's a really safe trajectory as far as room for error goes.

How many points do your think are lost to competitors who click and make errors clicking from zero down to 10 yards... I know I made that mistake a lot when my WFTF class scope was 3.5"CtC above my barrel, in my early days of FT.

 

[Franklink]

In reference to the last two posts...

I've been using a Ghost .20 in Hunter (mostly) for the last 6 or 7 months and about as many AAFTA style matches. Scope height is large with the Ghost/Alpha/Delta platform. Similar to @scotton s example of the .177/13.43s, when I'm using the .20/13.73s I've got a 0.8mil holdover at 55 and a 4.5mil holdover for 10 yards. The 4.5mil holdover @ 10yards sounds bad, but it comes with a 0.6mil holdover at 50 and a 0.8 holdover at 55. That difference of 0.2mils pretty much eliminates missing a 55yarder by erroneously thinking it's at 50, or vice versa.

My USFT also has a rather high scope height, but is the opposite end of the spectrum of trajectory rainbow for 20fpe ft. Shooting the 10.34s at around 920fps. Even flatter for the far shots, but also creates the problem of either alot of holdover or a lot of clicks for the close shots.... And as @Airgunoregon mentioned, the potential for a brain fart. Only once did I get off an entire revolution in a match with that gun, but it most certainly cost me some points before I figured out I hadn't returned to zero on the turret after a 10 or 11 yarder.

I view scope height in a similar way to the slower better BC versus the faster flatter discussion.....pros and cons both ways. Pick your poison.

As for ranging in the dark, it all comes down to knowing your equipment.

 

[scotton]

scotton,
In responding to the original poster, I was offering a potential solution/compromise that seems to help me. I'm using Air Arms 10.34 in a slow poly barrel in my USFT, that is producing a high BC in Hunter class at 19.5fpe. I'm using a zero of 30 yards. My holdover is very reasonable on both long and short shots.. overall my room for error is way less than if my scope was higher than the 2.25" it is now.

So, yes you are right under the conditions you are shooting within... heavier pellets, loopier trajectory, and clicking with a high power scope not set at 16x for Hunter class.

Even in Open or WFTF class, having 3 or 4 full turns to get from zero to a 10 yard target, in my mind is leaving a lot of room for error. When I shoot WFTF PCP class, I try to still keep my scope set at about 2.5 to 2.75" so I don't have more than one full turn when clicking from my zero to a 10 yard or 55 yard shot... but that's just what works best for me.

That 1.28" example you used is looking really good to me for a Hunter class shooter... especially a new one who might have a lot of things to learn about the game.. Keep it simple, seems like a good idea to me. I wouldn't mind fudging my zero and having a 1/16" hold under at 25-30 yards to make a longer flat spot in the trajectory.. again especially for someone learning the game. Most kill zones at 25 to 30 are 3/4" to 1", so being 1/16" high is not much of an issue to me... but even without doing that, it's a really safe trajectory as far as room for error goes.

How many points do your think are lost to competitors who click and make errors clicking from zero down to 10 yards... I know I made that mistake a lot when my WFTF class scope was 3.5"CtC above my barrel, in my early days of FT.

Sorry for the confusion, I was trying to point out that lowering the scope height will not give closer hold overs at long shots. Even though I was replying to you, I was really directing my post to the OP. You already know all of this stuff.

And, yes, I have dropped a shot here and there by being a turn out on the elevation knob, but not as many shots as I've dropped from ranging errors. My current setup is just shy of a full revolution for 10 yards, an advantage of having a 100 click scope instead of a 60 click scope.