NEW PRODUCTION THOMPSON CENTER BARRELS MADE IN NEW HAMPSHIRE. PLATFORM: THOMPSON CENTER Encore PROHUNTER. RATE OF TWIST: 5R RIFLING. 810 HEAVY CONTOUR ANY RIFLE FOREND WILL WORK FINE. FOREND SCREW SIZE/SPACING: 8-40 / 5 Centers. THREADS: Yes 5/8-24 THREAD. SCOPE BASE: DRILLED AND TAPPED FOR ANY STANDARD TC 4 HOLE BASE.