Since the “barrel extension” is an integral part of the barrel, the length stated is the true overall length.
For example, an 8” 9mm barrel has the same outer dimensions/length as a 7.5” 5.56 barrel.
Special Ops Tactical 9mm 3″ Nitride Premium Barrels are precision made using 4150 CrMoVa Chrome Moly Vanadium and feature a superior Nitride finish and 1/2×28 Threads for maximum muzzle device versatility.