Even if the bullet didn't breach the fabric, the fabric is gonna breach YOU. I guess it might make recovering the projectile from your internal organs a little easier, LOL. So there is that.
It would still serve to slow the projectile faster than it would be without, if you slowed the projectile enough so that it stops moving a sliver sooner; it could mean the difference between puncturing an artery or not.
> It would still serve to slow the projectile faster than it would be without
That's not even clear.
One of the common problems for bullet manufacturers with the "FBI protocol" suite of tests used to be the "heavy clothing" test. Shooting through several layers of denim would clog the cavity of the hollow point bullets and cause them to over penetrate.
Simply put, it's extremely difficult to predict how bullets will react to barriers of any kind in lieu of testing.
We haven't tested it for anything like this - so I wouldn't want to make any claims about the product when it come to something as serious being bulletproof. That said, theoretically it probably would have some sort of protective impact greater than having nothing at all. But again, not something we've done any testing on or can make any claims to.
Reading this subthread I'm imagining the slow-mo of a bullet hitting ballistics gel coated/covered with $generic_amazing_bulletproof_coating, the impact, and the ripple effect.
I can't help but wonder if something coated with something perfectly bulletproof might actually make things worse depending on the bullet's angle - for example, under ideal circumstances, a bullet could enter and leave and take out some fat - but if everything's covered, the whole surrounding area is going to get some serious bruising instead.