The invention relates to a floating double-
powder-chamber balance gun structure which comprises a front body tube, a first
powder chamber, a second
powder chamber, bullets, a
balance body and a rear body tube. The front body tube is a motion section of the
projectile; the first powder chamber is used for filling a first main charge; the second powder chamber clings to the
balance body and is used for filling a second main charge; the
projectile is a main launcher; and the
balance body is used for balancing
recoil force generated by launching the
projectile. Compared with the prior art, through the arrangement of the first powder chamber and the second powder chamber, the initial running speed of the projectile is increased on the premise that the maximum in-
chamber pressure of the balance gun is not increased; according to the invention, simple structure and principle are applied, the problem of high bore pressure caused by high initial velocity index of a large-
diameter barrel weapon can be solved, safe test launching of the
barrel weapon is realized, and the test device provided by the invention is simple in structure, simple to operate, safe, reliable, economical and practical.