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Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
USO new long range hunting scope
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<blockquote data-quote="LouBoyd" data-source="post: 540612" data-attributes="member: 9253"><p>Some thoughts and opinions on long range scopes. My backround is a long range hobby target shooter and build automated astronomical research telescopes as my professon. </p><p></p><p>Scope resolution at distances over about 600 yards in the daytime is limited by the atmosphere, not by the optical quality of the lenses. There are a few really junk scopes on the market. </p><p>Lack of contrast caused by internal reflections is the major thing which separates excellent scopes from so-so ones, but it's never seen as a specification in advertising. </p><p></p><p>More magnification at long range just makes the blur look larger. magnification beyond the point where the eye/scope/atmosphere resolution is less than aboout 1/4 of the rilfes group size at that distance is just a waste. More magnification just reduces the field of view and hurts target acquistion time. For target shooting at fixed distances magnifications over 20x >may< offer an advantage at moderat range. In my opinion only short range benchrest benefits from magnifications over 24x. High magnifications may help overcome some types of eye defects. </p><p></p><p>When scintillation is dominant larger objectives make the blur smoother. but it makes detail less visible. The image with a smaller objective will have more jitter, but more detail can be seen during brief moments. </p><p></p><p>The primary function of a riflescope should be aiming the rifle. Having a long eye relief guarantees a small field of view for a given magnification. If you want to search for game use a spotting scope or binoculars which can have a huge field of view compared to riflescopes.</p><p>That's not a matter of scope qualty, just basic optics. </p><p></p><p>Range can be measured accurately with several methods. Drop is easy to calculate precisely knowing range and air density. What isn't easy to measure is downrange wind deflection. It is THE major error source in long range shooting. Many shooters are simply in denial of that reality. They think expensive rifles and scopes will make wind deflection irrelevant. . High velocity rifles with low BC bullets does help but never makes wind deflection unimportant.</p><p></p><p>No scope on the market makes it easy to determine downrange cross winds. however, choosing a scope which will assist in determining crosswinds is better than one which won't. </p><p>Seeing the effects of "mirage" is easiest with moderate magnifications, moderate objective size, and the ability to adjust the scopes focus quickly and easily to known distances. The optimum scope is dependent on the conditions. Mirage may not be visible at all in cloudy conditions where the sun isn't heating the air near the ground. Mirage can be so bad that the target becomes invisible. A riflescope may be used or a separate spotting scope. Doping wind (with presently availabe scopes) can only be learned with lots of practice shooting. It's easy to see the air currents. Whats difficult is converting what you see to crosswind velocities and distance, and from that determining the bullet deflection. </p><p></p><p>Electronic croswind anemometers exist and they give about as good of performance at doping wind as a skilled human. The advantage of electronics is measurement speed. Skilled shooters rely on pattern recognition, not high speed calculations. I know of only one hand held instrument made to measure remote wind speed. It's sold for yachting, not shooting. . They are not a lot more complex than a laser rangefinder. Some R& D is needed to make a usable unit for shooters.</p></blockquote><p></p>
[QUOTE="LouBoyd, post: 540612, member: 9253"] Some thoughts and opinions on long range scopes. My backround is a long range hobby target shooter and build automated astronomical research telescopes as my professon. Scope resolution at distances over about 600 yards in the daytime is limited by the atmosphere, not by the optical quality of the lenses. There are a few really junk scopes on the market. Lack of contrast caused by internal reflections is the major thing which separates excellent scopes from so-so ones, but it's never seen as a specification in advertising. More magnification at long range just makes the blur look larger. magnification beyond the point where the eye/scope/atmosphere resolution is less than aboout 1/4 of the rilfes group size at that distance is just a waste. More magnification just reduces the field of view and hurts target acquistion time. For target shooting at fixed distances magnifications over 20x >may< offer an advantage at moderat range. In my opinion only short range benchrest benefits from magnifications over 24x. High magnifications may help overcome some types of eye defects. When scintillation is dominant larger objectives make the blur smoother. but it makes detail less visible. The image with a smaller objective will have more jitter, but more detail can be seen during brief moments. The primary function of a riflescope should be aiming the rifle. Having a long eye relief guarantees a small field of view for a given magnification. If you want to search for game use a spotting scope or binoculars which can have a huge field of view compared to riflescopes. That's not a matter of scope qualty, just basic optics. Range can be measured accurately with several methods. Drop is easy to calculate precisely knowing range and air density. What isn't easy to measure is downrange wind deflection. It is THE major error source in long range shooting. Many shooters are simply in denial of that reality. They think expensive rifles and scopes will make wind deflection irrelevant. . High velocity rifles with low BC bullets does help but never makes wind deflection unimportant. No scope on the market makes it easy to determine downrange cross winds. however, choosing a scope which will assist in determining crosswinds is better than one which won't. Seeing the effects of "mirage" is easiest with moderate magnifications, moderate objective size, and the ability to adjust the scopes focus quickly and easily to known distances. The optimum scope is dependent on the conditions. Mirage may not be visible at all in cloudy conditions where the sun isn't heating the air near the ground. Mirage can be so bad that the target becomes invisible. A riflescope may be used or a separate spotting scope. Doping wind (with presently availabe scopes) can only be learned with lots of practice shooting. It's easy to see the air currents. Whats difficult is converting what you see to crosswind velocities and distance, and from that determining the bullet deflection. Electronic croswind anemometers exist and they give about as good of performance at doping wind as a skilled human. The advantage of electronics is measurement speed. Skilled shooters rely on pattern recognition, not high speed calculations. I know of only one hand held instrument made to measure remote wind speed. It's sold for yachting, not shooting. . They are not a lot more complex than a laser rangefinder. Some R& D is needed to make a usable unit for shooters. [/QUOTE]
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USO new long range hunting scope
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