It depends on how far you are going to shoot. I have killed elk beyond 1000 yards with the 340 wby and a 250 grain sierra game king. My best load is 91 grains of 7828 at 3056 fps. This is out of a 28" barrel on a wby mk 5 action. The new 185 grain Barnes ttsx is a very good bullet to try that will make the 340 wby shine out to a half mile. It is very flat shooting with very little recoil and will drive through an elk easily at that range. If you are inside a half mile shooter that is where I would go. With your 30" barrel there is very little difference betwee the 340 wby and the ultramag cartridges so with the 300 grain smk you can do just about what the ultramags will. I have pushed the 300 smk to 2700 fps out of my 340 wby so you can see it is knocking on the door of the lapua and ultramags. My best accuracy load with the 300 smk is in the high 2600's. If you can hit elk accurately at 1200 yards the 340 wby is easily capable of killing it with that load.