No doubt JDJ has done a lot and is a great resource of information. However on this topic, he's had the use of some special 270 hornady bullets, or he only wants them to act in a high penetration situation?
They do not open at the low velocity the JDJ provides. Lets just use some common sense here. The 270 grain bullet was designed by hornady for a MV of 2800 plus FPS, that is Way faster almost 1000fps faster then the 375JDJ provides at the muzzle! It's also designed to be shot from a rifle that will be used on the biggest heaviest game that walks the earth. You bet your a$$ it's a tough bullet that is not going to open up on smaller game at lower velocity.
This is not bad in the JDJ cartridge, it might be the right option depending upon the application. However for Plains game and north American big game the 260 Partition was by a very large Margin far superior in lethal performance. It does not penetrate even close to the 270 hornady, but the bullets mushroom great and exit enough to be exactly what the velocity and cartridge design seem to be made for.
One something huge, the penetration of the 270 hornady wins, but for softer skinned game under 500 pounds or thereabout the 260 provides a great shuddering impact that is visible, where the 270 Hornady zips clean through with almost no visual impact. Having shot well over 100 animals in several countries with this gun I would take the 260 Partition 100% of the time for anything elk sized or smaller that is soft skinned, normal to light body structure. Example Black Bears, elk, deer, kudu, impala, black wildebeest, hartebeest, zebra, Mtn Lions, warthogs, smaller/female wild boar,
Animals to consider the 270 hornady, Brown bears, eland, moose, bison, blue wildebeest, larger/male wild hogs.
