Size is important.... when you're choosing the optimal dot size for your new red dot sight, of course. Brownells Gun Tech™ Caleb Savant gives us some pointers on how to choose the RIGHT dot size. Dots are measured in MOA (minutes of angle). The larger the MOA number, the larger the dot. A 1 MOA dot covers 1" of target at 100 yards, ½" at 50 yards, ¼" at 25 yards, etc. Any dot up to 3 MOA is considered small, 5 MOA is medium, and anything over 7 MOA is large.
A smaller dot enables more precise aiming, and at longer ranges, the dot won't cover the target. The downside of a small dot is that your eye won't pick it up quickly, and bright light - such as sunlight or a gun light at night - easily drowns out the dot so you can't see it.
The big benefit of a large dot is that your eyes will pick it up FAST, and it won't be overwhelmed by bright ambient light. It's great for close targets, but if the target's far away, a large dot may well cover it up. Example: a 7 MOA dot will cover 7" of the target at 100 yards.
As you might expect, medium-sized dots combine the benefits of both small and large dots. There is still some risk of a 5 to 7 MOA dot getting washed out by bright light, and your eyes won't acquire it as fast as a 7+ MOA dot. But the medium dot works well in many different situations. The dot size you choose ultimately depends on the type of targets you plan to address and your personal taste.
