LOL!! I realize that people believe what they want to believe, but still........
No one who knows a modicum about bolt action rifles will shoehorn a cartridge into too short of a magazine. A huge focus of the custom rifle building industry is to maximize the potential of each cartridge. This has been going on for years.
Many OEMs, probably in an effort to minimize costs, married themselves to a 3.4" magazine length. At first, it made sense, but it quickly reached the point of absurdity. The biggest example I can think of is Winchester putting a spacer in their 3.6" magazine boxes for many cartridges that worked better in longer magazine boxes. These cartridges worked better in longer magazine boxes well before the current trend of using heavy for caliber bullets. I have been removing magazine spacers, and shortening bolt stops and ejectors, on my M-70s for 20+ years. Later I started milling receivers to use Kevin Wyatt's magazine boxes.
Some OEMs broke the 3.4" restriction and Settled on 3.7" (Remington), but they became stuck there. Some OEMs like Tikka have regressed, offering a 300 Win Mag in their 3.4" magazine box. Some OEMs have done better, like CZ with their 3.850 length, but most of the solutions are in the aftermarket and custom gun world.
My company has worked very hard to address this well known issue. We have a DBM that will allow a 3.95" OAL. This works well on several premium aftermarket long actions and even a modified Remmy. We have a medium length DBM that allows 3.4" in certain medium actions, and we have a 3.15" magazine that fits certain short actions. Given the popularity of Tikka, we also make a 3.5" DBM and Mag for Tikkas.
All this make a huge different in performance. A long throated 300 WSM with a +P throat can shoot Berger 215s to 2900 fps+ from 22-24" barrels. A SAAMI 300 WSM can't even come close, IF you can even seat that bullet so the ogive is forward of the case mouth.
The 300 RUM and 338 Edge really need a 3.95ish COAL to be happy with heavy for caliber bullets, and the 338 Lapua IMP likes it as well. In the past, we just had to single feed these or accept too short of COALs.
In one of my M-70s, I installed a Wyatt's box (3.825"), long throated it, did a +P throat, and chambered it in 33-28 Nosler. It achieved 2925 fps with a Berger 300 OTM in a 26" barrel.
When it comes to straightish walled 458 cal cases, COAL is a huge factor in case capacity. The main reason to stretch maximize these COALs isn't to achieve higher velocities, it's to achieve the same velocities at a little lower pressure.
That is the main reason, along with building a Lott on my CZ, I'll be putting a Wyatt's box in my M-70 416 Rem. At 2430 FPS the 400 grain SAF hammered my buffalo, but in a 3.825" magazine box it will get that velocity at a little lower pressure. It will also allow me to better run 400 grain monos.
Long throats and long magazines are so common nowadays that it is beyond ludicrous to make the argument you are making about the 458 Win and 458 Lott. Anyone who can afford to go on a DG hunt can easily afford the few dollars it takes to optimize the magazine and throat on their 458 Lott or whatever.
