Does a 20” barrel maximize 5.56?

Were the YouTube personalities right about 5.56 velocity? Does a 20” barrel maximize 5.56 velocity and turn 55 gr into duty ammo? Does 5.56 slow down past 20”? Or are these guys frauds that fell for the Fuddlore and repeat lies without testing it for themselves? These answers and more! Disclaimer: ammunition was fired on a safe range in a controlled environment following all safety protocols and observance with local, state, and Federal law. No firearms, ammunition, or accessories are being sold through this video or any video on this channel. AR-15 5.56 ammo optimization, best 5.56 ammo for AR15, maximize AR15 performance, 5.56 NATO tips, AR-15 self defense ammo, prepper AR15 guide, minuteman rifle setup, SHTF ammo selection, AR-15 ballistics explained, home defense 5.56 loads, tactical AR15 ammo, best bullets for AR-15 defense, survival rifle optimization, prepared citizen firearms, AR15 ammo testing, 5.56 vs 223 Remington, AR-15 twist rate ammo match, minuteman loadout 2025, prepper rifle essentials, AR-15 accuracy tips, defensive AR15 build, SHTF rifle ammo, AR15 for home defense, 5.56 green tip vs hollow point, AR-15 ammo stockpiling