You need to remember in the US they predominantly have unlimited sighters with 20 shot strings...and the biggest ranges seem to be in the desert where high temps can, and are a factor. This is why the 284 and its improved variants are still the most popular - it's an inherently accurate workhorse which is proven out to a 1000 yards in the right shooter's hands and can handle 25 shot strings for example.
The reason the 7SAUM is so popular here (Australia) is that we generally have 2 + 10 matches, or the occasional 2 +15. That makes a SAUM much more appealing as the barrel temps are more manageable under string shooting.
