A couple of years ago, I tested a 24" barrelled 260 with all available factory loads and a bunch of handloads. All loads were tested for expansion, accuracy, velocity, and penetration in saturated newsprint. My favorite all-around bullets were the 125 grain Nosler Partition, and the 129 grain Hornady. The gun also handled bullets from 85 to 160 grains very well.
The one bullet that performed very poorly was the Nosler 140 grain Partition. At long range, it lacked the velocity to open reliably. In this test, long range was only about 200 yards. The tips of the bullets didn't expand evenly, causing the bullets to tumble and penetrate backwards. The "forward" portions stopped, and the rear cores exited the jackets and travelled on a short distance, even showing some expansion. This happened every time at long range. Sure, it would have killed a deer, but other bullets performed far better.
It may have been a bad batch of bullets, and the 140 grainers performed well at short range, but I think that 140 grain Nosler Partitions are best reserved for larger cased 6.5mm rounds. The 6.5mm-06 class and larger would be fine.