John Browning
A very good quick overview of John Browning's inventions can be found over at The Truth About Guns (not to be mistaken for the Truth About Guns podcast):
When Browning passed away on November 26, 1926, he had 128 gun patents to his credit. Despite his extraordinary accomplishments, his legacy sometimes flies below the radar since Winchester, Colt, Remington (Models 8 and 24 semi-automatic rifles and Model 11 / Sportsman shotguns), Savage (Model 720 shotgun), and FN brand names appear on most of the guns he designed, not to mention the millions of military arms manufactured that bore no brand name whatsoever.
Needless to say Mr. Browning knew his shit.