I have been reading with great interest the posts on this site and have gleaned a lot of information.
I am currently in the design phase for a new long range rifle. my current long range gun is a .300 Weatherby Accumark. The hunting I do requires quite a bit of horse back riding or walking to get into undisturbed areas.
I will limit my shots to 700 yards or less. This rifle will be used for elk, deer, antelpe and hopefully sheep and mountain goats.
I want to use a Remington Sendero action and stock. i will add a Jewel trigger and have the action blueprinted. I want to use the 7mm Ultra Mag. In a 28" Christesen Arms carbon fiber bull barrel.
I would use the 168 Gr Match King in the 7mm.
I use them in my 7/300 Weatherby Mag. with a 30 inch barrel and they have done will out to and much further then you plan on hunting.
PS After re-reading your post, I'm not sure if your looking for a bullet for the 300 or one for the 7MM RUM? 168 for the 7mm and the 200 or 220 Match King for the 300.
All three of these bullets have a much better BC then the Nosler BT in the lighter bulets. This means they (The Match Kings) will shot flatter and deliver more energy at extended range.
Try powder such as H870, REL 25, H1000 and Rel 22.
For a hunting style bullet I would also consider the 150 grain 7mm Swift Scirocco - it has a very high BC and has performed well for us on game. ALso good very good accuracy, some groups going under 0.5". I must admit that we have never shot an animal at real long range with the 7mm, but we killed some bears out to 200 with excellent bullet performance.
I have shot the .30 Scirocco (165 & 180) to 500 on game with excellent results. We recovered a bunch of bullets from wild hogs shot out to 500 with over 80% retension and very uniform mushrooming. Have also had great accuracy with the .30's.
Barnes also makes an interesting .30 cal match grade 168 "X" bullet that would meet accuracy requirement out to 1000, not sure how it would perform out there. We shot a bunch of them out to 1000 on targets, shot under 1 moa all the way with the .308 Win.
Last summer we shot some factory hunting bullets out to 1000 in 100 yard increments and they were stable and surprisingly accurate. Used Failsafes, Power Points and Ballistic Silvertips. Shooting was with the .300 WSM and a .300 Win. mag.
No doubt there are other good bullets to consider, these are what I have experience with.
I just knew you were going to say that. HeHe
I have only shot one whitetail with a Sierra Matchking. Fired from a 7 WBY mag, the bullet took him broadside in the chest from about 100yds. Deer made it into the freezer quickly. The 52gr Matchkings are quite lethal on groundhogs out to 500yds but it seems that the bone of contention here is Matchkings and "big game".
However, I am one of the guys who is more comfortable using a controlled expansion bullet. My recommendation for a big game, longrange bullet in 7mm would also be the 150gr Scirrocco. I have had good luck (accuracy-wise) with this bullet at full throttle in my 7STW.
BOTTOM LINE: When in doubt, listen to Darryl