No problem with FMJ bullets in a Krag.  Any .308 bullet will work as long as it's loaded within acceptable pressures (below 40,000 CUP).  That said, the Remington and Hornady ammo are generally good for hunting and accuracy is average.  Better accuracy is achieved with handloads and bullets that take advantage of that 30 inch barrel.  Just like humans, not all Krags like the same foods.  Some prefer the 220 gr RN loaded to original .30 Army specs... while others like 180 gr Spitzer bullets.  I have a friend who wins matches shooting a 150 gr RN bullet.  Also, not all Krags will feed spitzer bullets reliably - some hang up, some won't feed without problems.  If you do resort to handloads (like so many of us do), you just need to find what works best for you and your Krag!