I’m definitely not a guru, but a few advantages you get.
Long action (mag) performance from a shorter action. Shorter bolt throw. You pick up a little more “usuable” length in the barrel since they aren’t chambered as deep (compared to 7mm RUM). Plus, the powder burn is more even. I’m sure any one of these points can be argued.
One very distinct difference I noticed when comparing the ballistics of the 270win Vs 270 WSM and 7mm RUM was the PSI of the charges. The 270WIN was on average 10,000PSI lower and the 7mm RUM & the 7mm WSM was about the same as the 270 WSM. Then after comparing all the ballistic info, I felt the 270 WSM was the best over-all for me. with a 140gr Barnes TSX bullet out of the 270WSM, it carries almost as much punch as the 7MM RUM, but with almost 20grains less powder. Plus, I like to shoot all year long. I may shoot 100 rounds one month, 400 rounds another, and only 50 the following….but at the end of the year I burn a lot of powder. Nothing like the pros that are shooting 100’s per day, but it adds up.
Since I started shooting Barnes TSX solid copper for hunting, I really haven’t looked at other manufactures for the last few years. For me and my style, I don’t like bullets that fragment. I like a good mushroom and a heck of a lot of energy to blow through and damage the vitals. This year was very unique in that we had 3 whitetails shot almost in the identical spot. Each was off center through the chest and exit behind the opposite front shoulder. In all 3 cases, the deer never moved beyond 15 yrds.
Buck #1 – Shot 270 WIN/130gr Barnes TSX at about 100 yrds. Lungs were nearly cut in half, arotic was cut, and obvious signs of bruising to the upper parts of the heart. Blood was immediate at the location of impact and huge where it dropped 10 yrds later.
Buck #2 – Shot 270 WSM 140gr Barnes TSX just under 200 yrds. Looked like a cannon ball hit him on impact and he fell about 5 yrds from impact. Hit left off center of chest and exist out opposite shoulder. No lungs left – all stringy mush. Artery was blown off of heart and the entire heart was black and blue (but never a direct hit). Everything inside the upper cavity looked like it was hit, though you could see the distinct bullet path.
Doe – Shot 270 WSM 140gr Barnes TSX just over 350 yrds. Identical damage as buck #2
Now, compared to the last couple deer I shot a few years ago with Hornady superperformance and Remington Pt.
*Shot buck through lungs broadside – deer ran 200yrds with minimal blood trail.
* Shot buck dead center mass of chest. Deer looked like an accordion as he rolled over backwards. Got up and ran. Took 3 hours to track and find him, only to have to shoot him again. Bullet hit center mass chest and followed the external side of the rib cage and exited out his rear end.
Buck – shot broadside standing in my food plot. Bullet went behind shoulder and out of chest. Hit lungs, but absolutely no other damage inside. Deer ran well over 200 yrds with minimal blood trail.
As for the thought of a 270WSM being too large for whitetail?????? Not in my opinion. Call me morbid, but I want to see an impact and an animal fall DEAD. I intend to kill whatever I am shooting at. I want mass damage to vitals and for it all to over with immediately. I’ve been finding that the combination of more power and the Barnes bullets I am doing so much more damage to the vitals and a LOT less damage to the shoulder meat. I’ve been able to recover more meat around the impact zone than ever before.