This is a Tactical Solutions Barrel known as the X-Ring, model 1022OS-MB.
THE NEW X-RING OPEN SIGHT .22LR BARRELS ARE MACHINED FROM 6061-T6 ALUMINUM" THE PREMIUM X-RING BARREL HAS BEEN DESIGNED TO MAKE YOUR RUGER(R) 10/22(R) RIFLE LIGHTER AND SIGNIFICANTLY MORE ACCURATE. THE X-RING BARREL FITS ALL RUGER 10/22 RECEIVERS AND MOST AFTERMARKET 10/22 STYLE RECEIVERS. ACCURACY IS ENHANCED BY A RIFLED CHROMOLY STEEL LINER WITH A POLISHED 11 DEGREE CROWN. THE X-RING OPEN SIGHT BARREL COMES WITH AN ADJUSTABLE GREEN FIBER OPTIC REAR SIGHT AND GREEN FIBER OPTIC FRONT SIGHT.
Features:
Fiber optic sights
1/2X28 thread pitch
1:16 rifling