a feeder elbow comprising an entry end, an egress end, and a pivot axis;

a non-rotating launch tube having a longitudinal axis, an ingress end, and an exit end, the ingress end of the launch tube disposed to abut the egress end of the feeder elbow, the abutment of the ingress end and the egress end defines an interface, the feeder elbow pivot axis being disposed rearward of the interface and transverse to the longitudinal axis of the launch tube;

a pivot adjustment assembly disposed at the pivot axis connecting the feeder elbow to the supporting stand in rotational tilting engagement, the pivot adjustment assembly comprising an anchoring transverse column connected to the feeder elbow and having a longitudinal axis coincident to the pivot axis, the pivot adjustment assembly having a tiltable mode wherein the pivot adjustment assembly facilitates the tilting of the feeder elbow about the pivot axis and a non-tiltable mode preventing tilting of the feeder elbow about the pivot axis, pivot adjustment assembly is in the non-tiltable mode when secured and is in the tiltable mode when unsecured.