How is GP-11 not a truly strong Army Service cartridge? It is more powerful than .303 Britishicon, and it is compariable to 7.62 NATO, .30-06, and all the other cartridges of the era which were about the same in terms of velocities and energy (some a little higher, and some a little lower, but all within the same general range).

Standard .303 British loadings can easily get out to 800m, with no issues. They can go farther than that as well provided you do your part.