But Kel-Tec’s low-cost, polymer hefty layout philosophy has come back to Chunk it sometimes. Many of Kel-Tec’s QC and design issues is usually traced to the heavy use of polymer in their firearms, which could crack or be molded out of spec.The Kel-Tec P17 ships with three Journals, a lockable hard case in addition to a threaded muzzle adapter.