Most scope reticles have simple mechanism, especially the common types. But there are times that you will be encountering complex reticles, especially those in Germany. In this article, the common types of scope reticles in North America will only be discussed. These are crosshair, dot, and post and crosshair.
By far, the most popular scope reticle is the simple crosshair. This is usually available in fine, medium and heavy. Fine simple crosshair reticle is great for varmint hunting whereas the medium simple crosshair reticle is good for big game hunting and is for all-around use. On the other hand, the heavy simple crosshair reticle is perfect for close range shoot at large targets like deer. The simple crosshair is fast and much easier to use.
The post and crosshair is the next most popular scope reticle. The post was designed to look like a flat topped front sight and for those with iron sights or have problem adjusting to a crosshair scope reticle. Post reticle typically has a flat top. The tip of a post with a pointed edge or a picket fence post is very difficult to see at dim light. As a result, the shooter aims farther down the scope reticle and thus shooting above the target.
Below the post top, the horizontal crosshair is attached to maintain the rifle at balance. It does not have an aiming function. Currently, most shooters are more accustomed to telescopic sights making post and crosshair reticles less common.
The earliest Lee Floating Dot was suspended with strands of spider web. These reticles were the finest and the strongest. The stands of spider web were virtually invisible so that the dot will appear to float at the center of the field of vision. The dots are sold in various sizes and made to subtend at 100 yards for two, four or six minutes of angle (MOA). The four minute dot is good for big game hunting.
In 1950's, the old Weaver Company has begun selling a Range-Finder reticle. This type of reticle has additional crosshair 6 MOA under the central horizontal crosshair. The concept was that the body of the buck with an average size would have no empty spaces between the crosshairs at 300 yards to give the shooter a good estimate of the range.
During the 1960s, the scope reticles became more complex because of the Duplex reticle designed by Leupold. The Duplex reticle has fine central crosshair. It transitions to a strong crosshair about ¼ toward the edge. The concept was to guide the eye to the aiming point of the scope reticle. The heavy part of the Duplex reticle is much easier to see in the dim light. Also, the fine inner crosshair can be finer compared to the typical medium crosshair. Overall, the standard Duplex reticle is very versatile.
Leupold Duplex is the most imitated scope reticle design. Almost all of the modern scopes today are the version of this reticle. Today, Duplex type reticles are generally called "plex" reticles.