30-06 for myself a little bit slower velocity. But it’s hands-down better 100 grains of change when handling loading. But those magnum calibers tend to deflect when hit brush when 30-06 keeps going. I have used a lot of calibers. And I’ve never been more pleased with 30-06 300win mag is great at 350plus yards 243 is great, but again 100 grain bullet so you have to be careful 270win you can’t hit anything in my experience lol I’m not trying to take shot through brush but as hunters it happens I live in the deep east 308 great cartridge highly recommend. 7mm mag needs to be 300yards 175 grain bullet 270swm and 300swm 250 yards and out just over penetrators 25-06 can’t hit nothing 6.5 creedmoor I don’t have much experience but family members. They say it has great front penetration but it doesn’t expand crazy amounts but what do you expect out of a 270 basically I love the idea of the bullet super flat but just not good for close quarters brush it depends on what kind of Whitetail hunting as us hunters do I always encourage people to take a clear shot but as we all know we may not get it.!
I’ve shot a 6.5 for years and was using hornady 143 grain and they would do the same thing just zip through and never expand all the way. But I’ve swapped to a winchester deer season xp 125 grain and it is wild at the difference it makes. It has outrageous ballistics groups great out of my gun and they’re decently priced, should definitely give them a look. But if those don’t work from my experience with deer any smaller grain bullet will be better for expansion the smaller the animal the smaller the grain. Those 143 are made to expand and kill elk which is about 2 and a half deer side by side😂 which would explain why it passes through so fast and don’t expand as fast on such a smaller sized animal like a whitetail. Hope this helps anyone who reads.