SCJ429 wrote:But the 243 can shoot a 107 grain bullet in excess of 3000 fps and with a bit of coaxing at 3100 fps. This is about the same speed a 260 can produce with the same weight of bullet but worse BC. Hitting a goat at 500 metres with either projectile would be quiet similar but the 243 has the edge. It is like comparing the 7mm08 to the 308, they are very similar but the 7mm has the edge.
Certainly, it can by running it very hot, but you can do the same with the 6.5x55mm or 7mm-08 if that's how you roll. With the larger calibres you don't need to work the rifle that hard to make up the shortfall. You could also go with a .240 Weatherby if you really want to get the most out of 6mm bullets, but you're still only achieving what larger calibers can already achieve without all that heat, noise and expense.
At 500m the 3000fps 107gn SMK has about 460mm of drift in 10mph of crosswind. The 6.5x55mm with the 143gn ELDM at 2650fps (without having to push it hard) has the same wind drift, and 20% more energy.
I like the .243 but it is not in the same class as the 6.5mm or 7mm chamberings.
The .243 and a few cases of 87gn VMax ammo will deal very effectively with most of what a lot of shooters are likely to want from their rifle.