Grew up reading Elmer and learned from his writings how to hit at long range with a sixgun. 600 yards is a bit much but a fair sized 12" gong at 200 yards is certainly doable. Once hit one 4 out of 6 shots with a J-frame Model 34 .22, much to the chagrin of someone who told me it was impossible. Once you find the hold repeating it isn't too difficult but as with long range rifle shooting, wind is your biggest concern.
Elmer also related the story of hitting an outhouse at 700 yards with a 1911 .45. He walked the shots in, adjusting his hold until he hit it.
Reading that story I always wondered if he checked that outhouse first to see if it was occupied...
