Low hits

[mike a]

As the morning goes by I see my poi drop by around 1/2 moa. The rifle is a Ruger PR 6.5 creed. I've been shooting alot lately at 500 prone. I'll shoot 5 and go check the target, so plenty cool time. As the air temp goes up and the mirage becomes lite I see the drop. May sound crazy but I believe I've seen this drop with lite mirage often. It almost seems the target sinks a little as the mirage is just starting. Of course I've also seen way high impact with heavy mirage. Sun is also getting higher. I wounder if I should (lights up, sights up)This is a representation of 120 or so shots over 3 different days. Notice the majority are below center. Thanx mike

 

[ClassCat]

If the boil is up the wind is usually down. Running mirage is another story. Let ups have a tendency of producing lower groups because there is no condition to hold the bullet higher. Without wind flags this is just a guess, but a proven one with flags.

 

[dkhunt14]

If you put the crosshair on a target and watch throughout the day, the crosshair will move. Matt

 

[mike a]

If you put the crosshair on a target and watch throughout the day, the crosshair will move. Matt

Funny, looked to me like the target was moving. Me being so steady an such. But seriously, have you ever noticed the target sink alittle just as mirage is coming on? Mike

 

[dkhunt14]

Funny, looked to me like the target was moving. Me being so steady an such. But seriously, have you ever noticed the target sink alittle just as mirage is coming on? Mike

Yes, moving is mirage. But over a period of time, the crosshair will change without any mirage. Set a gun up and let crosshair on a target and check every couple of hours during the day and record movement. It might answer some of your questions. Matt

 

[Albany Mountain]

Your lights up, sights up statement probably holds true in this case. The intensity of the sun puts a glare on the target, basically forcing the visual image of the target downwards. You are aiming at this "lower" image of the target and shots are following accordingly.

 

[Dusty Stevens]

Yes, moving is mirage. But over a period of time, the crosshair will change without any mirage. Set a gun up and let crosshair on a target and check every couple of hours during the day and record movement. It might answer some of your questions. Matt

So is that why nobody can work up a load letting the barrel cool off between shots? All day long 5 shot group?

 

[fatelvis]

Your lights up, sights up statement probably holds true in this case. The intensity of the sun puts a glare on the target, basically forcing the visual image of the target downwards. You are aiming at this "lower" image of the target and shots are following accordingly.

And with ARs and M1As in highpower comp, it usually required 1/2 MOA up or down to correct for the lighting conditions, so it makes sense. I always thought it was due to the way the light was hitting the front sight though. I Learn something new every day!

 

[JFrank]

So is that why nobody can work up a load letting the barrel cool off between shots? All day long 5 shot group?

Dusty
I don't follow that please expand

 

[Depart123]

Light direction changes target perception, so does the refraction from the differing layers of warmer and colder air between you and the target. The amount of change is dependent on the number and intensity of those thermal interfaces and the angle of those interfaces to the shooter.

All of this, is in relation to the conditions you zero'd in, which is another variable. There is no single solution.

 

[Shawnba67]

At last 1k match we had patchy cloud cover. had a couple shots go 1moa high then back down asked a seasoned shooter what happened. He replied that i missed the sun coming out at the target then clouds came back and poi returned. I am smart enougn to observe it, but sadly not smart enough to understand it!! lol

 

[dkhunt14]

At last 1k match we had patchy cloud cover. had a couple shots go 1moa high then back down asked a seasoned shooter what happened. He replied that i missed the sun coming out at the target then clouds came back and poi returned. I am smart enougn to observe it, but sadly not smart enough to understand it!! lol

I hate when the clouds are patchy. Hard to tell if not looking through the scope when it happens. Unless it is a big difference. When your busy feeding shells and working bolt, it is easy to miss it. Usaually about a 3 inch difference in impact. MATT

 

[Shawnba67]

I hate when the clouds are patchy. Hard to tell if not looking through the scope when it happens. Unless it is a big difference. When your busy feeding shells and working bolt, it is easy to miss it. Usaually about a 3 inch difference in impact. MATT

Had i caught it i would have broken into the 190's for the first time!!
I will be watching next time!

 

[Kurt Blasser]

If you put the crosshair on a target and watch throughout the day, the crosshair will move. Matt

Why?

 

[Kurt Blasser]

I hate when the clouds are patchy. Hard to tell if not looking through the scope when it happens. Unless it is a big difference. When your busy feeding shells and working bolt, it is easy to miss it. Usaually about a 3 inch difference in impact. MATT

So patchy conditions, during the cloud cover, you shoot and hit POI, but when sun comes out target is visually pushed lower and now POI will be lower? Do I have that correct? Thanks!

 

[Dusty Stevens]

Dusty
I don't follow that please expand

If you wait too long between shots everything changes- wind, and over a longer period of time the light conditions. Trying to shoot a group waiting between shots will make some huge groups. Hard to work up a load with a slow gun much less having other factors to consider.

 

[dkhunt14]

So patchy conditions, during the cloud cover, you shoot and hit POI, but when sun comes out target is visually pushed lower and now POI will be lower? Do I have that correct? Thanks!

I have noticed about a 3 inch rise when sun comes out. Maybe from a full cloud cover to bright, it might be a little more. Matt

 

[BenPerfected]

If you wait too long between shots everything changes- wind, and over a longer period of time the light conditions. Trying to shoot a group waiting between shots will make some huge groups. Hard to work up a load with a slow gun much less having other factors to consider.

Dusty, my process when working on my tune is to shoot 5 shot groups in the morning for about 1-1.5 hr. between 7:30am to 9:30am during low winds. I could obviously see the groups POI change but didn’t know why. I am starting to believe that shooting at 500 yds for score may beyond my skill level. Sounds to me that shooting for score takes significantly more skill. Not going to stop shooting, but think I will put the trophy room on hold.
Ben

 

[Shawnba67]

Dusty, my process when working on my tune is to shoot 5 shot groups in the morning for about 1-1.5 hr. between 7:30am to 9:30am during low winds. I could obviously see the groups POI change but didn’t know why. I am starting to believe that shooting at 500 yds for score may beyond my skill level. Sounds to me that shooting for score takes significantly more skill. Not going to stop shooting, but think I will put the trophy room on hold.
Ben

If it was easy it wouldnt be any fun!

 

[Dusty Stevens]

Dusty, my process when working on my tune is to shoot 5 shot groups in the morning for about 1-1.5 hr. between 7:30am to 9:30am during low winds. I could obviously see the groups POI change but didn’t know why. I am starting to believe that shooting at 500 yds for score may beyond my skill level. Sounds to me that shooting for score takes significantly more skill. Not going to stop shooting, but think I will put the trophy room on hold.
Ben

Dont stop or get discouraged. Thats what sighter shots are for- youll be right back on. Makes you tilt your head like a dog though when folks tell you about killing those 800yd deer and how difficult a first round hit is