Long range marksmanship is definitly an advantage but another real important part is skill at identifying the animals at a distance.
For me, locking onto the correct animal is more difficult than the shot.

I hunt alone and use 40X binocs (pretty standard). Often in the short time it takes to shift from my binocs to my scope, animals have shifted and I no longer have a posititve ID.

Other factors add to the difficulty - antelope shift around a lot, and the does sometimes have horns - sometimes bigger horns than you would think. Dust, heat waves and shimmers, shadows, and poor light conditions play a part. I've even made the mistake of shooting a smaller animal when a larger one was there to be had. I'm pretty confident in my shot out to about 400yds but I find that the longer the shot, the longer time it takes for the setup.

Having a spotter helps a lot. I am sure that good magnification on a scope helps a lot, but I don't have that.

40X binos, and you hunt alone?? Holy cow!!! I take it you don't get very far from your vehicle carrying those heavy optics around. I typically hunt with one other partner and only carry 10X40mm binos and even find those to be a bit cumbersome. Actually thinking of investing in a pair of 8X30mm binos myself.

The 40X was a mistake. My bad. Mine are just normal magnification.

Ah, you were probably thinking 40 as in millimeters, the size of the objective lense eh?

My brother and I hunted Antelope in northern Nevada this year. It was our first Antelope hunt. The shots he took are listed below.

1. 85 yards at brush level in heavy winds (30 knots)
2. 135 yards at a running target (came 3 seconds after 1st shot above
3. 425 yards with the antelope about 500' above our elevation.
4. same as 3
5 300 yards trotting towards us about 250' above us.
6. 210 yards about 75' above us.

There was one day we just couldn't get closer than about 600 yards without something spooking them. That included a Cessna, two F-15's, other hunters or us. Oh, and we missed all six shots. Scope had been bumped waaayy out of whack on the first two shots. The rest the scope was sighted in to 150 yards using a .308.

My longest is 200 yards. I would definetly want to be comfrontable out to 350 or so.