Brownells: A top-shelf Geissele Super Duty
https://www.brownells.com/firearms/...AUTOMATICS+LLC&avs|Special-Filters_1=In+Stock
GrabAGun: DEL-TON heavy barrel with MAGPUL furniture
https://grabagun.com/del-ton-sierra-316-fde-223-rem-5-56-nato-16-inch-30rd.html
https://www.brownells.com/firearms/...AUTOMATICS+LLC&avs|Special-Filters_1=In+Stock
GrabAGun: DEL-TON heavy barrel with MAGPUL furniture
https://grabagun.com/del-ton-sierra-316-fde-223-rem-5-56-nato-16-inch-30rd.html