With three years or so total experience learning (still learning) precision rifle - shooting, ballistics, reloading, etc. - I shot the mile for the first time last week. A few thoughts:
- I shoot a custom 6.5CM (well, 2 of them) with handloads running around 2800fps - good rig for 1200-1400 yards. Can't stay above transonic further than that with sane loads. See story below for shooting the mile.
- When you get out past 850 or so, you're going to be far more affected by wind, light, and mirage than coriolis, spin drift, etc. Forget about them until you have a lot more experience at more than 1000 yards.
- Effects of light and mirage are surprising at longer ranges. I have found I can do head shots on an 850-yard IPSC quite well early in the morning. But when sun gets high and mirage starts swirling, just getting consecutive hits on a desired quadrant or half of the plate gets harder.
I recently joined a venue with multiple ranges, each with lots of frequently-painted steel out to 900-1300 yards and one range that goes to a mile. I didn't even try to go beyond 1100 yards the first day. I got hits out that far, but they were not consistent. I was pleased with consistency out to 750. But it confirmed my need for more experience at 1000+.
On the second trip, I joined a buddy of mine (who may well read this and comment) who was eager and straining at the bit to shoot the mile. It was his first trip to this venue, maybe the first time shooting a mile. He had a 7mm RemMag for the occasion. The wind was blowing steadily - sometimes gustily - 8-12mph full value left-to-right. It took him, I think, 4 shots to hit the 48"x48" square plate at 1760 yards. So then he went after the glory shot at a 12" round plate at the same range. Short story, he hit it twice. Twelve-inch target. One mile. Holding 4-6 mils left in the gusty wind.
So I tried the big plate with my 6.5CM. It took about 8 shots or so for me to hit it; I held something like 22.7 mils up and 6 mils left. Terminal velocity was somewhere around 1075fps... Too many shots were no-calls; but the ones we could see... a couple hit high, a couple low, a couple left/right. We're talking over a full mil between highest to lowest spotted shots. So, in my mind, shooting a mile with a 6.5CM is doable but there's a fair amount of luck involved, especially in the wind, so I claimed victory with one hit and quit.
Interestingly, my buddy had as much trouble as I did hitting the 48"x48" target with his 6.5CM. Since he had no trouble pounding it with his 7RM, it's safe to say the 6.5CM isn't "optimal" for the range.
It was so windy that day that all the shooters on the 1200 range were struggling with the furthest targets, and I recognized some very skilled marksmen from matches I've shot. Once again, I could do pretty well out to 850 yards, but beyond that... more practice needed.
Bottom line is, you're right: shooting at 1000+ yards is way different than shooting 500-600 yards. My take is, based on my one trip, that shooting a mile with a 6.5CM is a stretch under any conditions. It's doable, sure. I'm not sure how much ammo I'll spend poking at it; I'm much more interested in becoming consistent at 1200 and in.