Abstract: A tie gun for tying elongated bundles with a polymeric material tape loop, the loop having overlapped tape lengths, the overlapped material being welded with an ultra sonic horn, this horn embodying a horn tip end which with a clamp, and an anvil arrangement holds the loop in such way that a tape stock section just upstream of the weldment is weakened by horn operation disrupting at least some of the molecular orientation in the material so that the stock can be separated from the loop with an upstream directed pulling force applied to the tape stock resulting in a severance that leaves no objectionable protuberance or tab at the weldment. The tie gun also includes a quick release for freeing a tape build up in the gun incident a tape feed jam. A face of the clamp, face surfaces of the anvils and the horn tip end define a funnel envelope to facilitate tape stock feed to tape loop forming jaws on the gun at the outset of a tying cycle.