I am a huge fan of the big 7mms, hell my 7mm Allen Magnum is about as high on the performance ladder as you can get, in fact its performance out strides many of the best bullets we have on the market as far as the bullets velocity limits.
That said, a 7mm for hunting past 1000 yards, in my opinion is questionable. Not for ballistic reasons but more for terminal reasons. Hell ballistically, they are very hard to beat. For example my 7mm AM with a 175 gr SMK loaded to 3550 fps has nearly 2100 fps of retained velocity at 1200 yards and just shy of 1700 ft/lbs of energy. These numbers may seem high to some but I had to use a BC of .680 to get my drops to match up with actual bullet flight so the 0.608 BC that Sierra lists seems to be quite low with this bullet. That said, I have used this bullet on big game(mule deer and whitetail) out to 900 yards and I can tell you that even with ideal shot placement, terminal performance is not all that great.
I have also tested the 169 and 180 gr Bergers loaded both right to around 3300 fps which I have found is their velocity ceiling in most cases. Because of the velocity limits, the SMK actually outperforms these bullets by a noticable amount out to 1500 yards. The Berger bullet is a softer bullet for sure, expands a bit more easily but at ranges past 1000 yards they also have limits on terminal performance.
In my opinion, Without the 200 gr Wildcat Bullets which are supposed to be shipping again, the 7mm family is best left to 1000 yards and less. Even with the 200 gr ULD RBBT, shot placement at ranges past 1000 yards is CRITICAL. Yes it is with any bullet or chambering used but the smaller the bullet, the lighter the bullet, the MORE CRITICAL it is.
I am not saying a poor shot with a larger caliber will result in a quick kill, certainly not. What I am saying is that a shot on the fringes with a larger caliber, heavier bullet will ALWAYS result in BETTER results then with a smaller caliber, no matter what 7mm your shooting.
It also depends on what game your hunting. Deer under 200 lbs are a much different story then northern deer which can routinely hit +300 lbs and at times push 400 lbs. The very best long range bullets are not overly impressive as far as terminal performance which is to bad. If we could get the terminal performance of the 160 gr Accubond in a bullet with a .650 to .700 BC, we would really be onto something.
The big 7mms will do amazing work on deer size game at some totally extreme ranges but shot placement is critical meaning you better put a hole through both lungs for best results. Only pop one lung and you will likely never see your target on the ground unless your lucky.
In my opinion, the 7mm family NEEDS good bullet expansion to perform properly, in my opinion again, this occurs at ranges under 1000 yards on game 400 lbs and lighter.
For elk size game at 1000 yards and beyond, I DO NOT recommend a 7mm as a primary weapon for this purpuse. It can be made to work but there are vastly superior choices to be had.
On the topic of barrel life, I tend to get a chuckle out of this topic. Most SERIOUS shooters will not put 300 rounds of ammo through their rifles in a year. The vast majority of shooters will not put 100 rounds down the barrel in a year. And, even with less then 100 rounds down a barrel you can easily maintain proficency with a long range rifle. For example, When I go out to field practice with one of my rifles, this being after load development, ballistic confirmation and rifle zeroing has been done. I will generally shoot 10 to 20 rounds per session at most. This is by finding a target of opportunity, say a rock which I like to shoot at sub 1/2 moa sized rocks for field practice. I will set up the rifle, range the target, figure the ballistic hold and fire a shot. Take notes of there was a miss and at times take a followup shot but most of the time I will take a single shot.
You can spend 1/2 a day doing this and only put 10-20 rounds down a barrel, if your shooting more then one rifle, its often less then this.
So lets take an average, say 15 shots per field practice session. IF I did that twice a month during the entire off season I would only have 300 rounds down the barrel each year except for hunting season which generally amounts to 3-5 shots all hunting season.
In reality, where I live here in Montana, seldom do we go out and shoot in the months of Dec, Jan, Feb simply because the weather seldom allows us to do this comfortably. So figuring that we have from March until Mid October to shoot our rifles in field practice sessions, again, That is roughly 7 months, Thats 210 shots a year.....
Again, in reality, most of us will not get a serious long range shooting session twice a month. Some do, do not get me wrong, but most of us, even those of us that shoot 3-4 times a week like I do seldom shoot with our personal hunting rifles. more then once a month. That brings us down to around 100 rounds a year, again, plenty to stay proficent if done correctly.
Point being, you will likely see 800-900 rounds of barrel life out of a 7mm Allen Magnum on average. Some last more then this but this is on average if the barrel is not overheated and cared for properly. Figure you will have 100 rounds in barrel break in, load development and ballistic drop chart validation on average. I generally do this in less then 40 rounds but thats a different story, we will use 100 rounds.
That leaves us 700-800 rounds of barrel life once the rifle is ready to hunt with. Or in other words, 7-8 years of barrel life IF you put 100 rounds down the barrel a year and most will never get close to this level of shooting. In reality, I would say you would get 12-15 years of useful barrel life in a 7mm AM class rifle if cared for properly.
And at that, once you burn a barrel out, for another $700-$800 you can have a completely fresh barrel fitted, threaded, installed, finished and muzzle machined for muzzle brake
and your back to a brand new rifle. Thats less them most quality factory rifles and 1/3 to 1/4 the price of a complete rifle.
So, my opinion, no 7mm is fully adequate for +1000 yard big game hunting. In my business, you have to be conservative because if your not, some customer will call you up and chew your rear because he hit a buck of a lifetime on the diaphram at 1200 yards and lost the animal and that would be my fault because the relatively small diameter 7mm bullet did not do enough damage to the rear of the lungs and liver to drop the animal soon enough to be recovered whereas a larger caliber likely would have done much better simply because of the amount of tissue displacement compared to the smaller caliber bullet.
It is also my opinion that barrel life is about 10% of the issue that most would make it out to be. ITs more a wives tale made up but those that do not favor extreme chamberings. Certainly these chamberings eat a throat faster then smaller chamberings but many things go into burning a throat in a rifle, very few have to do with the actual chambering the barrel is cut to!!! Add to that that most will never shoot enough to burn out a barrel and its really somewhat of a moot point.
To that end, I have had over a dozen shot out barrels come into my shop ranging from a 25-06 up to my 7mm Allen Magnum and 338 Allen Magnum and after several days of cleaning to get several pennies worth of copper out of the barrels, they shot like new again!!!
Do not overheat your barrel, break it in properly, do not let carbon fouling build up, do not let copper fouling build up and it will amaze you how long it will last you no matter the chambering.
heat a barrel up and keep shooting, let it get dirty and keep it that way and you will take 50 to 75% of the barrel life away from your rifle........
Sorry for the long winded post.