Taking about calibers on the section/squad level: I find it interesting that the Japanese changed from their 6.5mm to 7.7mm (a .303 and .30-06 hybride) after their experiences in China, even though it was in widespread (and quite successful) use for more than 30 years.

The Grendel sure is interesting for the section/squad organisation when using it in IW and LMG. But looking at the case profile - does it feed into a LMG w/o problems?