If you've spent any time shopping for an AR-15 or upgrading your current build, you've probably run into the same question over and over: does barrel length actually matter, or is it just a spec sheet number? The short answer is yes — barrel length has a real, measurable impact on velocity, accuracy, handling, sound signature, and even reliability. The longer answer is more interesting, and it depends heavily on what you're using the rifle for. This guide breaks down exactly how barrel len …