Have you shot anything you mentioned? .30-06 and .308 are both quite powerful, and you can feel them in your chest when fired.

An M4 (the only carbine I can think of in use by the military) is already a step down in boom as a 5.56mm; adding a suppressor makes that even less so. It’s like shooting a .22 at that point. As to SMGs, they’re all small caliber – 9mm, .45, 5.7mm…

All of the above, yes.

I'm saying that a SEAL shooting a suppressed SMG feels nothing after dumping magazine after magazine downrange. There's no way this is causing concussions.

Grandpa's 30-06 will rattle your fillings a little bit after one round - still probably doesn't result in TBI.

That's not all SOF shoot, of course.

SCAR-H, M14 EBR, M249 SAWs and M240 all shoot 7.52mm x 51mm NATO (compatible with .308 but slightly different chamber pressures)

Sure, but we should be able to see if 0331 guys and the like have a higher incidence rate of suicide overall. Presumably they are spending far more time on these platforms than SOF.

The amount of shooting 0311 Rifleman does is fraction of what SOF does. The problem is accumulation of damage and no healing periods.

As I said, we don't if calibers below .50 cause significant damage when shooting in excessive amounts. Trying to figure it as a layman is useless. It's better to show epistemic humility than try to assert one way or another.

The FN Minimi (M249) fires 5.56. The others fire 7.62, not 7.52.

I shot a .50 a couple times and didn't feel much of anything tbh. Less of a shockwave than fireworks on July 4th.