The larger calibers with higher sectional density (SD is the key here) are capable of better penetration. On a full broadside shot this isn't super important...until the animal takes a step and your tight behind the shoulder shot placement turns into a shot through the shoulder blade. Or if the animal is at an angle, either toward or away, then you want a bullet with a high enough SD and sufficient velocity to get the penetration that you need. A 180gr bullet in a 308 versus the same bullet in a 300WM will perform much differently due to the 500 FPS difference in velocity. The 308 simply won't penetrate the same as the 300.
To get a similar SD with a 270 you need to run a 150gr bullet.. But that decrease in velocity creates a significant decrease in energy and momentum...35% less energy and 25% less momentum. That equates to less penetration. Even if you run the lighter bullet faster, say at 270 Weatherby velocities, it cannot equal the momentum of the heavier bullet. A person has to decide whether they want to plan for the worst case scenario or not. Your expected shot distance and angles play a part in deciding what cartridge to use. Going on an elk hun in an area where you expect lots of opportunity and have the chance to pass up an animal because the presentation isn't perfect? Then absolutely, take your favourite 257 Roberts or 308 Winchester. Going on a once-in-a-lifetime hunt where you have laid out a ton of cash to hunt a premium area and you REALLY want to take, not just any elk, but THE elk home with you? Maybe you want to opt for one of the larger rifles in your cabinet so that you feel more comfortable taking a quartering away shot at 300 yards.
The nature of the hunt and terrain should dictate your choice of rifles. I could choose my ATRS-built 300 Winchester with it's 5.5-22x scope for eastern whitetails just as easily as I could my custom Mauser 7x57. But the 300 weighs in at 13 lbs or more and has a 29" heavy barrel. Makes posting up inside my deer blind (think glorified outhouse) and getting the damned thing out the window much more difficult, all in the name of a maximum 50 yard shot. But that little Mauser with it's 18" barrel and 3x Leupold scope is absolutely perfect for the job. It's makes my buddy's Model 7 look like a farm implement. But if we were to take the same two rifles out to the parkland of Alberta and hunt the ostensibly same whitetail deer, the 300 would be a far better choice. The scenario could just as easily be applied to elk or moose...both rifles are absolutely capable of handling the chore and I would use either with equal enthusiasm, but which one would be the best choice depends entirely on the nature of the area you intend to hunt.
Are you sure that as velocity goes up that penetration increases? (With the same bullet of course).




















































