If you own an AR-15, you've probably stood in the optics aisle wondering whether a red dot sight is worth the investment — or if you should stick with your rifle's iron sights. The short answer: for the vast majority of AR-15 owners, a red dot is one of the smartest upgrades you can make. But like any purchase, it depends on how you plan to use your rifle. Let's break down exactly why red dots have become the standard choice for AR-15 shooters, and where they might fall short. What Is a Re …