FMJ yaw and upset performance

[Tony Williams]

And I would say well over 90% of this is anecdotal and pure opinion. Lets see the empirical studies.

I would say that there are three types of evidence which can be taken into account:

1. An accumulation of anecdotes from soldiers in combat (one by itself means little, if there are lots which are mostly saying the same thing, then it's worth paying attention). Given the immense burdens that they have to carry, I don't believe that soldiers would be willing carry the extra weight of 7.62mm guns and ammo (as they are, in both US and UK armies) unless they were satisfied that it was worth it.

2. Laboratory tests (there seems to be some sort of objection to testing ammo on live people, so substitutes like ballistic gel need to be used for comparison). Fackler and Roberts have both demonstrated the poor performance of 5.56mm.

3. The many attempts to improve the performance of 5.56mm, including MK262, MK318 SOST, M855A1 (and, of course, the 6.8mm Rem). If M855 were satisfactory, why bother to put in all this effort to improve on it?

Bottom line is that one has to prove a quantum leap in hit and kill probability before anyone will take a new cartridge seriously.

Not necessarily, if there are also other reasons for considering a change (e.g. to get a lighter round than 7.62mm, and to get one standard round, as I mentioned). And not at all if you're adopting a new technology like LSAT, where you're starting from scratch with all-new guns, ammo and production lines anyway. Then you might just as well go for the best solution, which as ARDEC recommended would be 6.5-7mm, and as JSSAP seems to have accepted in rejecting 5.56mm LSAT. But we can't expect the US Army to go for an intermediate LSAT unless the performance of the calibre has already been demonstrated in conventional form.