Both guns have a bolt carrier, rotating bolt, and similar amounts of fire control group components. Both need to be headspaced within a spec of a few thousandth

Both guns have a bolt carrier, rotating bolt, and similar amounts of fire control group components. Both need to be headspaced within a spec of a few thousandths of an inch. The biggest difference is about 20 years of industrial development (moving from stamped/milled steel to aluminum)