Browning was the best overall firearms designer...
Stoner produced the best RIFLE design of THIS century, with MK taking 2nd place...
This said because while Browning produced excellent pistols, shotguns and machineguns, he really didn't get a rifle design adobted for mass service. The BAR was deployed as a LMG/SAW, remember... Like Mauser/HK, Browning had a penchant for blowback operation....
Mauser, of course, deserves mention for designing the bolt action that became the template for pretty much everything since (Mod 1898)...
I wouldn't put Garand on the list, although the M1 was a unique design for the time, better designs were later produced, without following Garand's work. For example, the only thing the M1 and AR have in common action wise is the existance of a gas port & tube....
Eventually, someone may replace Stoner on my list, but only when a superior semi/full auto rifle action to the AR-15's is produced. This has yet to happen.