It’s rifled by hammer-forging with a 12-groove right-hand twist at the rate of one turn in 17.71 inches (450 mm).
LW 1:17,7BSA 1:19 (may be also hatsan at44 )Crosman recent barrel blank .22 1:15.5"Crosman old model 180 .22 1:15.5"Crosman recent barrel blank .177 1:15.5"Career Infinity .22 1:15.5"HW recent blank from MAC1 .22 1:16"FX Cyclone .22 (LW) 1:17.5"BAM .22 1:18"Sheridan C9 Rocker .20 1:12.25"Sam Yang 909 .45 1:20 (published)AA MPR .177 1:17.75Steyr .177 has different twist rate for different power.1:18,75 ... LP1:17,75.....MP1:15,75.....HP Steyr LG110 .177 (24J) barrel has 1 twist in 15 1/2 In. Thanks GS.Gamo CFX (Older metal trigger model) 1:25 (17" barrel)Weihrauch HW30MK2 1:15 (15.5" barrel)Weihrauch HW77K 1:15 (14.5" barrel)Air Arms MPR: Slightly over 1 turn in 475mm, rounded to manufacturer's spec of 1:450mm or 1:17.7".Air Arms S200: 1 1/8 turns in 485mm; giving a rate of around 1:430mm or 1:17".BSA Ultra: 2/3 of a turn in 290mm, giving a rate of around 1:435mm or 1:17"Weihrauch HW99s: 15/16 of a turn in 395mm, giving a rate of around 1:420mm or 1:16.5"Weihrauch HW100: 1 turn in 420mm, giving a rate of around 1:420mm or 1:16.5"