If you've spent any time around AR-15 forums or gun counters lately, you've probably heard shooters talking about "going subsonic." It's one of the more misunderstood corners of the AR-15 world — part science, part myth, and part trial-and-error tinkering. Whether you're chasing a quieter range day, exploring suppressor-hosted setups, or just curious what all the fuss is about, here's a practical breakdown of subsonic ammo and how it plays with the AR-15 platform. What Makes Ammo "Subsonic …