260 Rem 22" barrel

130 Swift H 4350 45.2 2,900 mv.

6.5-284 24" barrel

130 Swift RS Magnum 61.0 3,150 mv.

That's 250 fps difference between the two AND I'm willing to bet the 284 case did it with less pressure.

You could take 40 fps off for the longer barrel on the 6.5-284.

So say an extra 200 fps. That's the normal difference between a magnum case and a standard.

Well worth it to me.

With a 260 I get

120's at 3,020
140's at 2,800
No dif between it and a 6.5x55.