While scrubbing gun-cleaning schmutz off my hands, I noticed something. A person who knew what to look for could tell I shoot just by examining them.
There's a trigger callus on the medial side of my right index finger. A hammer-bite scar from my Hi-Powers in the web of my right thumb. And calluses on the palm of my right hand and the heel of my left from the aggressive G10 grips on my 1911's.
P.S. -- Eventually a hammer-bite scar doesn't even hurt any more when it gets bit again, but I do advise wiping blood off a blued gun promptly, lest it damage the finish. And when I hear the guys complain about grips or checkering hurting their poor wittle hands, well, they're obviously not shooting enough.