I would be shooting a different bullet if you want to shoot long range, but that's just me. That low bc 140 is gonna get pushed around a lot more and make it harder to get good groups in lightly shifting winds when compared to a 168 Berger or 162 Hornady eld. And if you have a 1-9.5 or tighter twist, there is no reason not to shoot the heavier bullets for long range, unless your trying to make a light recoil load. But if I was planning on shooting out to 800+ yards with a .280 Rem, I would go heavier.
If all your hunting is done at 400 and closer, than the 140 will do fine, and would probably give a better point blank distance. All I'm saying is that if your trying to get the most out of your rifle, it will be harder to get good groups in shifting winds with a bullet that has a G1 bc of .485 when compared to bullets with a G1 bc of .617, and once you get past 500 yards with conventional long range rifles, things change and you need to put all the advantages in your favor.
800 yard ballistics @ 6,600 ft elevation
168 Berger @2875fps:
10 mph wind: 3.0 MOA
Energy: 1781 ft-lbs
Velocity: 2185 fps
Drop: 15.5 MOA
140 NBT @3100fps:
10 mph wind: 3.6 MOA
Energy: 1481 ft-lbs
Velocity: 2183 fps
Drop: 14.1 MOA
Distance has to be a known quantity for long range shooting, and you dial/hold over anyway, so not as important as other factors unless your looking for farthest point blank range. The 168 has .6 MOA less drift, 300 ft-lbs more energy and is going about the same speed, but over more distance the 168's advantage will only grow because of it's higher bc. Just something to think about. Your 140 will do fine, but a higher bc bullet, even at a lower speed, would do better at long range.