FMJ yaw and upset performance

[stanc]

That unsatisfactory gel test of the FMJ bullet has already been used in a British report on future small-arms ammunition to discredit the effectiveness of the 6.5mm calibre...

Aside from the yet-to-be-answered question if adequate terminal performance can be achieved with 6.5mm FMJ "green" bullets, your mention of that gel test with the 120gr Norma FMJ brings to mind a nagging thought. In regard to using a single, 6.5mm cartridge for infantry, history tells us that it's been tried before, and was found wanting.

All the countries that I know of which used a moderate-velocity 6.5mm round, also had a more powerful, .30-.32 caliber cartridge for machine guns. Also, they all instituted a switch away from 6.5mm, some (such as Sweden) for political or logistical reasons, but others (like Italy and Japan) for perceived inadequate terminal performance.

Now, Italy's change to 7.35mm can be ignored because they used obsolete round-nose bullets in 6.5mm. IMO, they would have been better served by upgrading 6.5 Carcano to a (110-130gr) spitzer bullet.

However, in the 6.5 Arisaka cartridge, Imperial Japan had what is essentially a 6.5 Grendel Magnum. Nevertheless, they still began a changeover to a full-power, 7.7mm round, reportedly as a result of combat experience.

Since you're proposing, in effect, a modernized 6.5 Arisaka cartridge -- with slightly lighter bullet at slightly higher velocity -- what reason is there to think it would fare any better?