September 10, 2005, 05:39 AM
I need advice on sight adjustment under various light conditions, for instance, how to adjust the sights in case of morning light conditions vs evening light conditions, or sunlight coming from right vs coming from the left.
firing towards the sun or having the sun behind.
Also about the affect of the wind on the point of impact.
would there be a difference by the twist of the barrel?
September 11, 2005, 07:52 PM
If you're shooting north or south, and you shoot all day long, if you're a consistent shot, then you may find your groups moving toward the sun. (left or right). But unless you shoot all day long, you probably won't notice. Adjusting sights for this is not the norm. Shooting into or away from the sun, As if there was some magnetic pull on the lead and copper to adjust the projectile tragectory toward the sun, (not the case), is to shoot normally. -How the sights are set for not shooting into or away from the sun. As for morning or evening sight settings in low or limited light conditions, as long as you can see the target, and see your sights, then again, there's no change required. If you can't see them, it's time for glasses, some sort of glow sights, Or just possibly time to quite shooting.
Wind drift calculations can be found in in any reloading manual. The factor depends upon the bullet weight, velocity, caliber and design. I have some old Speer reloading manuals available for the price of postage if this is what you need. Reading a reloading/balistics manual will most likely answer many of your questions.
Rate of twist will not make up for the trajectory or wind drift. Rate of twist will inherantly affect overal accuracy of any particular caliber. Compare the lower twist rate of the 32Win Special in an early Win94 against the 30/30 in a Marlin or Winchester94. The Marlin is most often more accurate. With the 32Win the least accurate. The bullet isn't spinning as fast.
I'm surprised that you didn't ask about shooting up or down hill. The affects of gravity on a long shot. Again, information that can be found in most reloading manuals.
September 11, 2005, 10:16 PM
Basic rule for light conditions using a post and peep sight and the 6 o'clock hold on bullseye targets.
Sun up---------sights up. Sun down ------sights down.
The explaination is as follows...........
When the sun is out and shinning brightly on a target the target bullseye becomes larger and fuzzyer (sp) in appearance. therefore there will be more distance between the top of your front sight and the middle of your target. You must raise your sights to allow for this.
When the sun is down or on a cloudy dark/overcast day the aiming bull appears to be much darker or hard black in color and smaller in appearance. Therefore you must lower your sights as you will be holding closer to the center of the bullseye when it is setting on top of your front sight.
Unless you are fairly skilled with military stye post and peep sights you will probably not notice the shift in impact between overcast and bright days.
It has been my experince that wearing a shooting hat and sunshields on your shooting glasses will for the most part null out the effects of sun from your left or right sides.
September 11, 2005, 11:03 PM
It all matters. The light, The wind it all matters. With shorter distances it will effect you less than at longer ranges.
Whole books have been written on the subject of wind and light and how it effects the bullets flight. You can get cards made up from your loads over given yardages with wind at various speeds to get the impact. You can even get programs for your cpu to work out those details.
How do I feel all that helps a person? It gets you to a beginning place.
AS I mentioned else where We held a 600 yard clinic on sat. but because we had plenty of coaches and help a few of us did not have to teach so I did not. Instead 3 of us spent about 2 hours talking about the wind and its effects and how to read it. They both shot and did pretty well for the conditions before we talked on the wind. I said I will shoot a few shots and call out the wind before I shoot and have them watch and take mental notes of what they thought it should of been. All of my shots were no wider than the X ring with some above it and some below it but in up to 12mph switching winds. So say I called 3/4 minute left on one shot and the next shot was 1/2 minute right. both x's and so on. One of them was confussed but the other more experienced shooter said he saw a most of the calls but did not catch a few that I called as his call was different from what he was looking at compared to mine.
I called all the shots off of the mirage only this time and tried to point out the different ways to find what you needed to read to get the feed back. Where to find it and how to tell what it is telling you. Next time maybe we will sit down with scopes for like 20 minutes and every 40 seconds someone will say mark. Everyone will write down the call and how they saw it for 20 calls. Afterward we will sit down and talk about it and go over each call. A game plan for different conditions and how to control your shots in the conditions you have instead just going threw the motions. I will stop now as you could write another book on the subject but remember all the charts and programs will not get you the experience to just go out and say this is what I should do for 20 shots in a row one loaded round one at a time from a long distnce.
I could talk for hours on light effects also but its also better to get out and see and try to learn it also. If you use the range and your time on it to really learn you will have gained a great insight on a skill that few know well. I feel I am just starting to get back what I lost years ago and learning a few more things along the way.
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