Joke answer: Chachan is a shonen anime protagonist and will take exactly as many bullets as he needs to do the Dramatic Hero Thing. And then likely end up all beat up and bandaged but otherwise fine in the "next day" scene. Minus rampant Senzu Bean use.
In all seriousness, one of Chachanji's "strong" points (for good or for ill) is endurance and stubbornness. If the bullet doesn't hit anything vital, then he might whimper and whine about it... but would push on if it was something he felt strongly about. It probably helps that he's a pretty solid smith and tends to put his money where his mouth is by wearing what he makes. So, properly armored up he's even more likely to be able to withstand small arms fire (after all, melding a basic materia to a cobalt chain mail suit in the ARM questline made it strong enough to stop Limsan-level gunfire).
Judge is also almost always in full armor and surprisingly resilient besides. The others, though? No particular degree of bulletproofing. Especially Gaines - a strong enough light jab could double him over, let alone something as potentially fatal as a gun shot. At least Gogon might be able to have some aetheric protection or something up.
In all seriousness, one of Chachanji's "strong" points (for good or for ill) is endurance and stubbornness. If the bullet doesn't hit anything vital, then he might whimper and whine about it... but would push on if it was something he felt strongly about. It probably helps that he's a pretty solid smith and tends to put his money where his mouth is by wearing what he makes. So, properly armored up he's even more likely to be able to withstand small arms fire (after all, melding a basic materia to a cobalt chain mail suit in the ARM questline made it strong enough to stop Limsan-level gunfire).
Judge is also almost always in full armor and surprisingly resilient besides. The others, though? No particular degree of bulletproofing. Especially Gaines - a strong enough light jab could double him over, let alone something as potentially fatal as a gun shot. At least Gogon might be able to have some aetheric protection or something up.