Spotting round bore alignment mechanism for rocket launcher

A mechanism for providing fine adjustment to achieve parallelism of a spotting rifle barrel and a launcher tube is provided. The mechanism uses a convex spherical or near spherical surface on the rear of the spotter barrel which is mated to a concave conical surface on the spotting rifle receiver. The receiver is rigidly affixed to the launcher tube. The spotting rifle barrel axis is adjusted by means of three adjustment screws which act on a locating washer attached to the muzzle of the rifle. The locating washer has a spherical or near spherical surface whose radius center is co-located with the radius center of a second spherical surface supporting the breech end of the barrel. These spherical surfaces permit the free pivoting of the barrel about the common radius centers. A barrel gripping collar is moved into contact with the locating washer by means of a spring which forces the convex conical surface of the locating washer to engage the concave conical surface of the grip collar. This engagement creates a wedging action which causes the grip collar, which is split, to tighten onto the muzzle of the spotting barrel. The action of a spring causes the grip collar to be forced into the locating washer and also forces the barrel into the receiver. This spring also allows for barrel expansion, caused by heat during firing, without affecting the alignment of the axis.