If I throw this ball to a person in the parking lot and aim at their chest the ball may land at their feet or bounce before them. I have to aim high to have the ball land at their chest. Same with a bullet. If a target is yards away and my gun barrel is horizontal, the bullet will land low, just like the ball. And just like the ball, I have to aim higher to compensate for gravity's effect on my projectile.
How high depends on how fast I throw the ball and how far away my target is. The most popular reticles being offered today by almost all manufacturers have some kind of BDC bullet drop compensation reticle in them. On second plane scopes the magnification has to be set at a certain power for these to work, and you need known distances for these to be used correctly. A laser range finder is generally required. Again, most manufacturers will have at least one type of compensating reticle.
Keep in mind that second plane American scopes will only work at a certain magnification designated by the manufacturer. Riflescopes in the first plane that increase the size of the reticle along with the target may be used at any power. Some way of range estimation is required for any compensating reticle. Again, use laser range finders. The lines in the reticle excluding the cross hair are called Stadia lines, and are used as aiming points for holdover.
Beware, these are not exact. There are too many variables in gun barrels, ammunition, temperature, elevation, humidity, etc. When sighted in for a hunt at yards here, I was about 10 inches off in elevation at around feet where the air was much thinner and the temperature cooler. You have to actually shoot the gun at specific distances rather than rely on a chart of any kind.
Some reticles such as a mildot reticle can be used to calculate distance. Mil means milradian, not military. A radian is the angular measurement that is equal to the angle formed at the center of a circle by two radii cutting off an arc whose length is equal to the radius. A mil in a reticle subtends 3. Double that number for yards, triple for yards and so on. A mil is 36" at yards. To find the approximate distance to a target using mildot scopes you must first set the magnification at the required power specified by the manufacturer.
Then you must know the approximate height of your target. A man may be 6' tall or a torso may be 3' tall. Duplex: The difference between standard crosshairs and duplex crosshairs is that the outer ends of two or more of the crosshairs are thicker than the crosshairs in the center. The thicker lines make it easier to get a quick sight picture. Ranging: Horizontal lines along the vertical axis of these crosshairs help you determine the correct holdover for different ranges.
In most cases, they are set at approximate yard intervals. The trick is to know what each line represents for your gun and the ammunition you are shooting, because it can change with each type of ammo. These reticles are best used if you know the distance to what you are shooting at. In this case, you use the dots on the vertical and horizontal crosshairs to help determine distance, windage and holdover.
If you know how wide or tall something is, you can also estimate distance. For example, you know that something is 2 meters wide and that the distance between two of the dots on your reticle is 1 meter at meters.
If the object spans two dots, it is meters away. If it spanned one dot, it would be meters away. BDC: Ballistic or bullet drop compensation BDC reticles are similar to ranging reticles in that they have horizontal lines showing holdover for different ranges, but the distance between the lines is based on the ballistic characteristics of a commonly used round. Some like the thick circle for this purpose, while others think it blocks their view of the target and what is going on around it.
I tend to agree with the second group and prefer a ranging reticle with an illuminated center dot for quick target acquisition. Exit pupil represents the size of the stream of light coming through the scope. The green circle is the exit pupil of a 10x50mm scope 5mm , which is close to maximizing the amount of light the observer sees. The 8mm red circle is the exit pupil of a 6x48mm scope. If you tried to do this by looking at a target, your eye would have a natural tendency to look at the image first and not the reticle.
Shoulder your rifle, and looking at a blank image, simply turn the eyepiece until the reticle is razor sharp. Glass-etched reticles are far better than copper wire reticles that are typically used. The reticle is actually carved into the glass. Can make thinner and finer lines for long-range precision. Choosing the type of reticle for your rifle scope, and how it applies to the type of hunting or shooting you plan to use it for, is nearly as important as the scope itself.
You can still find rifle scopes with your basic t-plex crosshairs reticle, and these are very efficient. But again, as shooters evolve, so have the reticles with the introduction of various bullet drop compensating BDC and mildot reticles. The basic reticle provides your central aiming point, the crosshairs.
In the case of the T-Plex rifle scope reticle, we removed the thick top vertical post. This creates a cleaner field of view that allows you to get on the target quickly. BDC rifle scope reticles are designed to give you true points of aim at known distances to compensate for bullet drop.
Once you find your zero, the dots will give you an exact point of aim whereas a basic reticle would require a bit of guesswork. Each dot below center would represent yards - the second dot yards, the third dot yards, and so on.
The design helps the eye quickly focus on the aiming point and aim precisely with the thin inner lines. Without a doubt, duplex reticles are the most common reticle type and are popular among professionals and amateurs. Mil-Dot reticles use roughly the same layout as the Duplex, but they come with an interesting extra feature, small dots aligned along the reticle lines. The spacing between each dot corresponds to a specific angle, allowing the user to determine the range of a target if the size of the target is known.
The Mil-Dot layout is considered a standard for the military scopes and law enforcement snipers. Also known as Bullet Drop Compensation or simply as BDC, these reticles are extremely popular because they allow an accurate target acquisition at different ranges without the need of making adjustments to the elevation settings of the scope. BDC reticles fulfill their purpose by using a dot system similar to the mil-dot type. BDC reticles are usually optimal for short and middle range use, their performance dropping significantly when used for distances beyond yards.
Probably one of the most complex to understand types of reticles, yet really popular because of its impressive tactical features, the Wind Drift can be considered a hybrid between all the other types described above. Using a combination of crosshair lines, dots and horizontal lines, this reticle is ideal in acquiring moving targets or establishing wind drift. Manufacturers usually use thin crossed wires to help the user acquire the aim point.
However, crosshair reticles are the base of many more sophisticated models.
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