Steel alloy for Firearms

Research a type of steel alloy that is used in common firearms that have been produced within the past 50 years.

Reflect:  How does the type of steel used in firearms affect the overall length of its service life? How have the manufacturing processes of the modern era enabled gunmakers to produce high-quality firearms that will serve the test of time? Please feel free to include any of the finishing techniques that may be used to enhance performance as well.

Your submission must be a minimum of 500 words