Any experience with this round?

It appears these are built on a long action, seating the bullets way out.

142gr@3000 fps or so...

Maybe some guys out there have some .264win.mag. experience on game and can lend an opinion? or 6.5rem.mag, or 260rem?

the 6.5 has very high BC and known for accuracy, and light kicking.

Would one just be better off with a 280rem/AI or something more popular with good BC's?

Also does this round require 26" barrel? 24" 22"

My wife has a 6.5-284 Shilen (drop in) for her Savage 12 Varminter. Fantastic cartridge, very easy to tune for. HEAVY hitter on coyotes to 700yrds (farthest she's had so far), and great performance on deer. Like Ridge mentioned, if you're only wanting a 400yrd rifle, then the 6.5-284 is probably not going to benefit you much. The 12 is a short action. For really long seats, it's a single loading proposition, but it wasn't a problem getting things tuned to a COL that will run in her repeater.

There's actually been a shift for long range shooters back to the .284 Winchester, and the improved .284 Shehane (approx 100fps improved). The 6.5-284 is a barrel burner. A little nicer on barrels than a 7mm WSM, but not much. Hitting the magic 2950 with a 180grn Berger (published BC = 0.684)from the 284win might exceed your reloading manual, but there are plenty of guys doing it over the bench (Reloader 17). My next barrel will be a .284win Shilen...

I have a Remington XP100R pistol that is chambered in the 260 Rem cartridge. I bought from my dad awhile back and have used it to kill deer very effectively out to 250 yards with a 120gr. bullet, when my dad owned it he killed a couple of elk using the 140gr. bullets. It is a very accurate gun and a very good hunting round. I have been concidering getting one in a rifle, dont need it but would like to have it.