Only cup and core I've ever used on big game was Hornady Interlocks but have used those on mule deer and elk in the 7mm RM, .270 Win and .30-06 at impact velocities from about 2500 up to 3200 fps. They all stayed together well enough to do the job.

It's no longer in vogue to use SD as a measure of effectiveness, but for c and c bullets I stayed with bullets in the .240 range and up - 130 .277, 140 7mm and 165 or 180 .308 - and always got good expansion and penetration from various angles.

The fastest I ever saw an elk go down was a cow shot quartering toward me with a 180 grain Hornady Interlock from a .30-06 at about 200 yards distance. She went down so fast I couldn't see her when the rifle came down out of recoil and at first I thought I'd missed and she had run off. The bullet entered in front of the right leg and exited midway on the left side, leaving the chest cavity completely awash in blood when I opened her up.

Since you asked specifically about the .270, here are two Hornady 130 gr. 270 bullets fired at a MV of right around 3200 fps. Left one hit a 200 lb deer in the chest at about 100 yards, the right one was fired from a distance of 6 inches into that same deer's chest. Both lost a good bit of weight but held together to go all the way through the deer and were found under the hide on the opposite side.

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