The Ruger Mini-14 is a semi-automatic rifle chambered in .223 caliber. The rifle is based on the larger M1 Garand and is simple and reliable. The Mini-14 is generally considered a short- to medium-range rifle for engaging targets up to an distance of about 200 feet. Although the .223 bullet has an effective range of up to 600 feet, the Mini-14 is not designed for long-range shooting.
A variable-power scope features adjustable magnification. The recommended power scope for the Mini-14 is a 3x9-powered scope with a 40mm objective lens. This scope will give you an adequate sight picture at short ranges, which is where you'll be doing most of your shooting, but also gives you the option of increasing your magnification for longer-range shots. The objective lens is the front lens of the scope and is the primary source for letting light into the scope. The diameter of 40 mm will bring sufficient light into the scope to consistently give you a good sight picture.
Fixed-power scopes are preset at a specific magnification. When choosing a fixed-power scope for your Mini-14, keep in mind that you'll be generally shooting short distances. A 4-power scope with a 32mm or 40mm objective lens should give you great results. However, if most of your shooting involves targets that are farther out, approximate 200 feet, then you may wish to consider a 6-power scope.
Choosing the reticle pattern of your scope is really a matter of personal preference. Scopes generally come in one of two varieties of reticle, or cross hair, patterns. Conventional cross hairs feature two straight lines running vertically and horizontally. And tactical cross hairs feature ranging marks along the cross hairs. Both types of patterns will work well with your rifle. The advantage of tactical cross hairs is that it gives you the option of using your scope as a range finder.
Red-dot scopes are specifically designed for quick target acquisition at short ranges. Most red-dot scopes have no magnification quality and feature a red LCD light that is visible when looking through the scope. The LCD light represents the projected point of impact of the bullet, just like the intersection of the cross hairs of a conventional scope but minus the cross hairs.