This week, we’re taking a look at the Head Down Firearms HD-15 Master Series, the company’s top-tier modern sporting rifle offering. As such, the rifles feature billet aluminum upper and lower receivers, Nitride-finished CrMoV barrels, an upgraded M-Lok handguard, an 18-inch barrel version with a Luth-AR MBA-1 adjustable stock, a sub-MOA guarantee and more. Learn more about it in the video embedded above, hosted by Digital Associate Editor David Herman. MSRP: $1,939.99-$1,999.99; hdfirearms.com.