Can a soldier purchase upgraded equipment?

The only thing I remember about this was a problem with sub-standard bullet-proof vests that were given to soldiers when the 9/11 troops first arrived over there in the ME. It was awful.
Many families who could afford better quality materials, purchased safer vests and sent them over. Community fundraising and Corporations raised $ and donated many more.
Military about had kittens over it. Security-wise.
The Government should have been ashamed over giving those vests to people going on those entering into deadly situations.
I don’t believe any other extra materials are ‘officially’ recognized.
Try looking up the bulletproof vests as a base, and go from there.
Good luck.

Earn enough XP in the field and you can even purchase the unlimited ammo upgrade.

A sword would only be in the way for a grunt and armor would slow him/her down, even elevate the body enough to make for a better target. Stun guns aren’t needed because you have your rifle or pistol that uses FMJ ammo that is intended to not kill but only wound, plus it has greater range. Best to just adapt to the battlefield and pick up whatever you need along the way…