Do you have a plethora of empty lowers lying around from the last panic buy? Good news, there is another caliber you can build and it shoots cheap! I’m talking about converting your standard mil-spec lower into an AR 9mm lower. At only 17 cents a round, you can even let your mooch friends shoot it without going broke! Like to rapid fire? Like to load up 30 round magazines and dump ammo like John Wick? This is for you with its easy install and use of the venerable Colt 9mm magazines. So come on, you know you want an excuse for a new AR build!! Check out our complete AR-9 Uppers as a great combo with this!