Gear
Optics & Sights
An optic is a purchase where the specification sheet is the least useful page. Magnification range and objective diameter are easy to print; repeatable adjustments, honest eye relief, a reticle you can actually use at first light, and the ability to survive being knocked against a truck door are not. The single most common mistake is spending most of the budget on magnification and the remainder on a mount, when the mount is what determines whether the zero holds.
Before you buy
What to know about optics & sights
Budget for the mount before the magnification
A capable optic in a poor mount will not hold zero, and it will look like the optic's fault. Rings and mounts from a maker who publishes torque specifications, fitted with a torque wrench rather than an estimate, remove an entire category of frustration. On an AR, a quality one-piece mount at the correct height for your cheek weld does more for practical accuracy than another two magnification steps.
Match the optic to the distance you actually shoot
A red dot is faster than anything else inside a hundred yards and asks nothing of your eye position. A low-power variable covers close work and stretches to a few hundred yards. A fixed or high-magnification hunting scope earns its keep past that. Most people over-magnify: a wide field of view finds an animal that a twenty-power scope loses entirely.
First and second focal plane
A first focal plane reticle grows and shrinks with the magnification, so its holdover marks are valid at every setting, which matters if you range and hold with the reticle. A second focal plane reticle stays the same size and is only calibrated at one magnification, usually the highest, but it stays fine and visible at low power. Neither is better; they suit different shooting.
Battery life and reticle brightness
A red dot you leave switched on for years is a genuinely different tool from one you must remember to turn on. Check the stated battery life at a usable daylight brightness rather than at the lowest setting, and note whether the model has shake-awake. For a defensive rifle, a reticle you can see in bright sun is not a luxury.
Questions
Common questions
Red dot or low-power variable?
A red dot if nearly all your shooting is inside a hundred yards and speed matters: it is faster, lighter, more forgiving of head position and runs for years on a battery. A low-power variable if you want one rifle to work up close and identify or engage targets at a few hundred yards. Many people run a magnifier behind a red dot as a compromise.
How much should I spend on a mount?
More than feels reasonable. The mount is what holds the zero, and a good optic on a cheap mount behaves like a bad optic. Buy from a maker who publishes torque specifications, use a torque wrench, and check the screws periodically. It is the least glamorous part of the purchase and the one that most often decides whether it works.
Do I need first focal plane?
Only if you use the reticle to range or hold at varying magnification. Then yes, because the subtensions stay valid throughout the range. If you dial your elevation on the turret, or you shoot at one magnification, second focal plane is perfectly good and the reticle stays visible at low power, where FFP reticles can nearly disappear.