Fixing device and method for testing drift value of sniper rifle

The invention discloses a fixing device and method for testing the drift value of a sniper rifle. The fixing device and method are low in cost, short in testing time and safe. The fixing device comprises a base, an upper cover and a pressing arm are hinged to the base, a V-shaped groove is formed between hinge points of the upper cover and the pressing arm, a rectangular notch is formed in the upper cover, the pressing arm penetrates through the rectangular notch, a screw is arranged at the free end of the pressing arm, a nut is arranged on the screw in a matched mode, and the nut is used for pressing the upper cover to enable the upper cover to press the gun barrel. A bias current value testing method comprises the following steps: installing a base on a test bench, adjusting a gun surface to be vertical to the ground, adjusting a gun barrel to be parallel to the ground, and screwing a nut; setting target paper and aiming points; shot effect correction; after the gun face inclines leftwards by 90 degrees, a