My wife and I have used the same caliber, bullet design/weight, and zero for 20 +years. And...has worked very well for us from less than 30 yards to beyond 400 yards, on animals from Fox, deer/antelope, elk, bear, moose. Boring I know... but very effective!
As previously stated....keep it simple! memtb
300-400yds is where the advantage of the 2nd bullet begins. If you don't engage animals past 400yds, don't bother.
I've used two bullets for more than 20yrs. The real advantage has been in the past 10-15 years when I started focusing/preparing/planning for shots past 600yds. But all I've ever experienced is positive advantages.
Buck fever can make a mess of a situation even when using the perfect components.
The real value of the 2nd bullet and load is being able to select a bullet that outperforms each end of the spectrum, compared to hoping one bullet will excel at both close AND long range.
1) One bullet for high velocity impacts from the muzzle out to ~400yds. This bullet will never shrapnel/explode. It will always maintain a minimum of 50% of its original weight after impact, and more commonly ~75% weight retention.
2) One bullet for lower velocity impacts at ranges past ~400yds. Accuracy and certain expansion at the lower impact velocities are the priorities.
But I still experience excessive meat damage from Berger VLDs/Hybrids/Tacticals and Hornady ELD-M style bullets at fairly long impact yardages. Last season a 300gr Berger made a bigger mess of a heart shot caribou at 715yds than I cared for. So I'm in the process of converting over to Al-tipped monolithic bullets for long range use. The BCs are a bit less than the Berger and tipped Hornady variety of bullets, but good enough for my needs - which end at a maximum range of around 1000yds. The Hammer bullets are a good bullet by all accounts, and would be a great choice for the long range hunter that prefers a "one-bullet fits all".
I'm trying some AL-tipped lathe turned copper bullets first, because I've always preferred tipped bullets as I've experienced more reliable expansion from tipped lead core jacketed bullets. If these tipped bullets disappoint in any way, I'll likely order some Hammer lathe-turned copper bullets.
But I'll still carry a second bullet/load in my magazine for close range bear defense and harvesting game animals at closer ranges. Because the long high BC long range bullets I shoot are loaded too long for magazine lengths and/or I don't want their tips being slammed/damaged in the magazine during recoil. I load long range bullets single shot style after I've prepared for a long range shot. Up until that point, I'm carrying controlled expansion Swift A-Frame style bullets in the magazine. If hunting by myself, I may also hunt with one chambered, so I'm most prepared for a close range encounter of any prey or predator.