For an example of when "absolute reliability" was required - I look to my arctic grizzly hunt in the Brooks Range, 2017. I used my 30-06 rifle and handloads with 200 grain Nosler Partitions.

After a mile-long stalk, we found the bear at about 40 yards, perhaps a bit farther. Firing was fast and furious. I used all four of the cartridges in my rifle's magazine in less than a minute. At the end of the shooting, the bear was dead. Each round simply had to slip smoothly from magazine to chamber, fire accurately and with full power, and then eject, clearing the way for the next cartridge.



I'd loaded some cartridges that shot extremely well. However they were really long, seated to be close to the lands. Some were so long the bullet actually jammed into the rifling and then stayed there! The cartridge wouldn't smoothly eject if I didn't fire it. Backing off a bit with the length, was a good course of action.

Reliability mattered more to me in that case than the ultimate accuracy.

Regards, Guy