Do some research on em , watch some vids. Tactical edge arms wont bullshyt ya , call em up. Ask for bobby the owner. Use some google-fu . When i was in the market for a drop in trigger . I talked to tom verh the owner of velocity triggers , conversation turned to wpns and dlc bcg,he said his triggers had dlc on parts and he was wanting to produce dlc bcg,s also.his tech guy told him they cant be coated inside . I told mr verh that was b.s. and sent him pics of mine. Rrsearch em up . Mine has a rockwell hardness of 96.
