I know this is an old thread...but, I tried the 144 Lapua's in my 260 Remington, and they worked great. They cost significantly more than the 142 SMK though. With the price difference, and my shooting skill, both bullets easily shoot under half inch, but I'm simply not a bench rest shooter, and can't get enough difference in accuracy between the two to make the price difference cost effective.
I like the heavier bullets, but frankly, the 144 and 142 remain supersonic well past the distances I usually shoot, so I just don't need 2 more grains of bullet weight...especially not for the price difference.