yes it is 1/2x28 specs from cz site see ****Product Name CZ 805 Bren S1 Pistol SKU 91361 Firearm Type Handgun Purpose Home Defense MSRP $1,799.00 Chambering .223/5.56 Magazine Capacity 30 Magazine Type AR-15/M16 Frame Aluminum Grips Polymer Sights Flip-up