A tissue puncture closure device having an anchor, a suture, a sealing plug, a compaction assembly, a carrier tube, and an insertion sheath. The suture is connected to the anchor at a distal end of the suture. The sealing plug is slidingly mounted to the suture and positioned proximal of the anchor. The compaction assembly is operable to compact the sealing plug toward the anchor. The carrier tube has the sealing plug positioned therein during delivery to a vessel puncture. The insertion sheath is insertable through the vessel puncture and configured to receive the carrier tube and anchor. At least the carrier tube has a cross-sectional shape with a greater width dimension than a height dimension.