As a companion topic to wing flags, I thought this might be a good subject.

I have been "caught out" with light changes as much or more than wind changes.

At a shoot last April, I had my Iron Sights dialed in, Right on the center of the 25. I had more than 10 shots on paper at the time. I moved over to the record target and and the first shot was a 23 at 4 o'clock. I thought, it was a bad bullet or the wind switched so, the next went right beside it and the wind was fairly calm but, the light was changeable (partly cloudy). It ruin my target so, I just kept shooting w/o changing the sight setting. I got 2 more shots in that group and then it started to climb back to the edge of the 24/25 ring. I then made a sight change and got 2 or 3 in the 25.

What I didn't know at the time was, it happened to everyone and had I made the change back to the 25 after the second shot, my target would have been competitive. It was my first big match in 15 years. 

I used to shoot single shots back in the '80's with a extremely good High Power shooter and it was he that schooled me on wind and light. As I remember about light changes, the target appears to rise in the direction of the light source so, brighter light will make it look like it's higher in the direction of the sun, so a shot with a brighter light source will cause the shot to hit the target lower in the direction away from the sun.

Keep in mine that you see nothing, the only thing you can actually see is the light reflected off a object.

Am I remembering this correctly? What are others thoughts on this very important (for shooters) subject?

Frank

SchuetzenDave, can I get your thoughts on this subject?

Frank

My Schuetzen and Small bore Prone experience is Aperture sights on bulls eye targets don't change point of impact  one way or the other enough  to make any difference due to light differences. Light will make the ring around the target more difficult to resolve.  So light does affect the target but by less precise point of aim rather than forcing aim one way or the other. You can correct for this with the rear aperture size.

Post front sight like on a Service Rifle or NRA rule CLA rifle is another matter.  When light changes I get fairly large elevation changes.  2 moa at times. Our club matches on Ram shaped steel swingers  and Cowboy lever silhouette I use a post front.  Probably fired 600 or so rounds in competition with post this year. I keep track of every shot and can say perhaps half of my misses have been high due to getting caught out in variable light.   Years ago when I shot service rifle same thing high shots when the light goes dim. You know it when it happens but it's very difficult to catch yourself before the shot is fired.

I have never seen much in the way of windage change with post sights due to light changes.  Of course every body's eyes are different and so are rifle ranges. How the range is oriented relative to the sun may make a difference

Yes changes in light intensity will change your sight elevation. Even on a clear day at Raton the brightness of the sun early in the mornng versus a brighter sun at noon will change the elevation you are shooting at. Ussually changes are half to a full minute; but can be even more at times. When you get two or three minutes of elevation change it is ussually a mirage boil.

40 rod has it right.

Sights up. Lights up.


But also do not forget as you shoot longer strings your barrel gets dirtier. and you will also get a slight drop in elevation as your barrel gets dirtier. Yes I always have to adjust my sights slightly to stay centered in the bulls eye to maximixe my score. Light, wind and rifle performance need you to correct your sight alignment as you shoot numerous shots over a longer period.

Guess we will have to get better at it. Jack Odor set a new record of 1249/1250. Pretty fabulous record. Need to have him tells us how he adjusted his sights at Raton.