A: Because our carriers are NiB we do not need to chrome line them. Here our the specs:
PISTON BOLT CARRIER SPECS:
Bolt Carrier Material, 8620
Bolt Carrier Nickel Boron Coating
Bolt body produced from AISI 9310 VAR (Vacuum Arc Remelt) and Nitrided, Extractor produced from MIL-S-5000 steel and vacuum hardened
Answer provided by: Black Rifle Arms Sales Team (9/1/2022)