Add that the "less than steady shooting position" and that's enough to explain the misses.
Everytime I get fired up about reaching out beyond 300 yds., I usually try it out under field conditions. That's means no benches rest or other really solid rest. That means with whatever wind is present unless it's odviously too much wind.
That alone usually does it for me. Especially if I'm hunting something as tough as a bull elk. E
