The Solitary War of the Sniper

In last nights "episode", Furness was observing the enemy at about 600 yards away with his 20x scout regimental telescope and spotted what appeared to be a high ranking officer.  With a single shot from the T, the senior officer fell.  The repercussions of that action nearly got him killed; they threw everything they had at Furness: she!!ing, mortar fire, machine guns, the works.  He was very lucky to have escaped alive.  He was deaf for over a week from the exploding she!!s all around him.  

It is hard to imagine the stress of moving forward of your own lines to observe, and try not to get caught for it would usually mean immediate execution for being recognized as a sniper.  

I got to thinking about just how difficult it is to hit a man sized target on the first (and only) shot at 600 yards with a No. 4T.  Even with the 3x scope, that's a pretty small target to hit (a 14" wide chest is just over 2 minutes at 600 yds).   

Furness was clearly a master at range estimation, there were no range finders in that day!  I'm hoping he explains somewhere in the book how range estimation was done, there is not much to go on using the graticule post to estimate range, the width is 8 minutes.