The utility model provides the air guide hoop pinhole anchor clamps that drill and ream, its technical essential lies in: it comprises cylinder components, rotatory briquetting, air guide hoop locating piece and barrel mouth locating piece, cylinder components drives rotatory briquetting and plays clamping action to the barrel excircle, and the position location is done with barrel mouth locating piece to becoming the rifle to air guide hoop locating piece. It improves part positioning accuracy by barrel and air guide hoop piston hole location, and clamping device adopts pneumatic clamp tight, makes the clamping part more convenient, more reliable, improves the clamping process velocity and guarantees the productivity effect. The utility model discloses a clamping device beneficial effect: under the condition that does not change firearms processing property, the barrel is fixed a position on V type locating piece, and air guide hoop piston hole is epaxial in the location, and part positioning accuracy is higher, and press from both sides tight piece design through 45 angle rotation formulas for easier clamping of loading and unloading spare part and dismantlement are saved time, and firearms product quality obtains guaranteeing.