Rammer, I know exactly what you're talking about. Sometimes you just can't get close. And I will still stick by by guns and say that no one should attempt any shot they are not comfortable with.I too practice at 300 and sometimes 400 yds. Especially on a year when I will be going on a western hunt. The open prarie county can make stalking difficult at times and it seems like the wind is always blowing. And its my opinion that the wind is a much more difficult aspect to overcome than holdover.
For those of you that want a good read on the effects of wind. Check this site out. http://www.6mmbr.com/Winddrift.html