10mm pistol with 25 points of bleed damage. I don't even use pistols, but this thing is extremely powerful, because the bleed damage stacks, the bleed damage doesn't care how little damage the actual bullet does, the bleed damage doesn't care where you hit the enemy, and the bleed damage ignores armor. It's actually the strongest weapon I have to deal with super mutant behemoths and mirelurk queens and all those kinds of crazy tough enemies. I can just spray this pistol at them and watch the damage pile up as all those dozens of bleeds occur. The only way this could be even more ridiculous is if it was a .38 weapon, so I would be able to burn the most abundant junk rounds in the game on taking down the toughest enemies.
Actually, the most OP weapon in the game would probably be a minigun with that kind of a bleed proc, because every single tiny bullet would also come with that sweet sweet armor ignoring extra damage and just melt face.
From a balance standpoint it would really be sensible if they changed the bonus damage property on those kinds of items to a percentage, since having it be static per shot just makes it go out of control with weapons that shoot lots of cheap bullets very fast, but nearly worthless on slow shooting weapons.