FMJ yaw and upset performance

[JASmith]

As far as 77 grain 5.56's are concerned, I have the strong impression that no calibre smaller than 6.5mm is likely to prove acceptable as a replacement for 7.62mm, in terms of penetration and terminal effectiveness. The Chinese tried to make a universal cartridge with their 5.8x42 (in light and heavy loads), but their army is hanging onto their 7.62x54R MGs.

Tony, you are probably on the mark with the 7.62 observation. The debates here haven't gone to the level of detail as they have in your Military gun and Ammunition forum. For this reason, not everyone here will instantly concur.

Further, it would seem that there is wisdom to carrying more than one hypothesis forward until at least the time a new cartridge is adopted by one or more significant military. The value added is that, especially if your position is ultimately shown to be the best realizable option. the debate will have shown that and the adoption decision will be more clear-cut.

This would suggest at least one hypothesis that has the 7.62 maintained as the "heavy" and a "light" that is somewhat more capable than the current 5.56 NATO.

One of the "light" options could well be something like the 77gr MatchKing that LR1955 mentioned and that the reporting indicates that it is be liked and respected by the troops using it.

Another might be a larger case in either 5.56mm or 6mm.