Are there any instances of regular bullets piercing Wonder Woman's skin in specifically the New 52 (post-Flashpoint) continuity?
Given her power level upgrades, at least until the New 52, Wonder Woman SHOULD have been easily bulletproof, because in almost all other ways, she would have been as tough as Superman or Captain Marvel. But like all things comics, there was a great deal of inconsistency on that point. We don't know what the pending Rebirth of the DC Universe will do to her powers.
The New 52 Wonder Woman was merely a continued rise to power for the character. Her bracers had graduated from protecting her from the bullets in the Man's World (their Golden Age purpose), to deflecting the weapons of other gods like Ares, or weapons from alien worlds, whose destructive capacity was unknown and thus best avoided.
For Wonder Woman's bracers to make sense, you have to remember when the character was conceived, she was neither bulletproof nor invulnerable. Despite her powers and resistance to damage from things like explosions, she could be harmed by arrows or bullets which placed a lot of energy on a piercing point.
To prevent being harmed by these kinds of attacks she would do her "bullets and bracelets" thing and escape serious injury. This Wonder Woman would exist until some time late in the Silver Age or perhaps right up to Post Crisis where she was given a major reboot and an increase in her powers.
Post-Crisis Wonder Woman had an inconsistent level of durability. "Tough enough for a punch from Superman, but still vulnerable to bullets?" was the question lots of people began to ask when she still used her bracers to deflect bullets. This inconsistency would track depending on writers even into the New 52.
During Post-Crisis and later versions of the character, she acquired a magical, molecule-splitting sword and nigh-invulnerable shield. People would question her needing bracers even more.
Ultimately, her bracers became more iconic, a representation of what the character used to look like, even though she used her bracers half as often as she once did, and in some cases, didn't appear to need them.
But writers appeared to handle it on a case by case basis and sometimes there was no consistency in the display. It even became the core of jokes around the topic, making it even more difficult for fans to reconcile.
- At the end of the Zero Hour Era, (before the New 52 DC Universe) Wonder Woman was already powerful enough to fight and survive a full-out brawl with the Man of Steel. Though she didn't win that fight, it pretty much made her the top tier superhuman female character in the DC Universe.
In an epic battle, she is tackling a mind-controlled Superman (See: Maxwell Lord) who is fighting full out. The battle ends up in space (note the SUN behind them) and Superman punches Wonder Woman, hitting her so hard she passes out while she flies from the sun, at the speed of light, to hit the Earth and survive!
The New 52 Wonder Woman was even more powerful than the Post-Crisis Wonder Woman having powers which rivaled Captain Marvel (Shazam) and more than capable of surviving a nuclear blast at point blank range. She does so hugging it out with her beau at the time, the New 52 Superman.
- During the Injustice: Gods Among Us series, Wonder Woman is shown being completely unaffected by 5.56 Nato rounds. She doesn't bother to deflect a single one. While this particular Wonder Woman isn't the mainstream universe version, it pretty much illustrates that Wonder Woman at a power level strong enough to punch Superman in the face is pretty much going to ignore anything that looks like a bullet.
Coincidentally, the mainstream Aquaman who is only half as strong as Wonder Woman is shown to be bulletproof as well, so if it's good enough for him, it should be good enough for her.
Bulletproof? Yes, let's go with that.
In the New 52, her bracers were also described as a containment or limiter on her godly might. Without them she was even MORE powerful, if you can imagine that, and had the potential to go berserk, hinting at her maybe even killing foes that drove her to that point. Note: Her bracelets are weighted...
Wonder Woman's bracers have not lost their usefulness. Wonder Woman doesn't always wear her shield or her sword, saving them for really terrible situations like alien invasions, dimensional incursions with multiple metahuman level opponents and the like.
When New 52 Wonder Woman faced Supergirl, she used her bracelets to protect her from Supergirl's heat vision, known to reach temperatures of 6,000 degrees, definitely a recipe for sunburn...
- As such, her bracers still function as they always have: to protect her from attacks which might be more than she wants to have to tank in order to continue to fight at peak efficiency.
Amazonium was the name of a metal used for the construction of Wonder Woman's Bracelets of Submission. These bracelets, created by Aphrodite were to remind them of the cruel submission the Amazons suffered under Heracles. In the classic tales of Wonder Woman, binding the bracelets together removed an Amazon's abilities.
The bracelets have thus far proven indestructible and able to absorb the impact of incoming attacks, allowing Wonder Woman to not only deflect automatic weapon fire, energy blasts and other projectile weaponry.
Wonder Woman Vol. 1 #52, 1952
Due to her being the daughter of Zeus in the New 52 comics she has different powers than before. Being bullet proof seems to be something she has acquired in this series of comics. Her bracers (gauntlets) are now used not only as shields to deflect things but they also keep her "god powers" at bay.
It is rather inconsistent, for sure, but the latest version (Rebirth) is definitely NOT bullet proof... In both issues #19 and #21 WW is shot and wounded by regular high-powered rifle fire. https://www.cbr.com/wonder-woman-bulletproof-or-not/
Makes no sense considering her nigh-Superman power level, but it is what it "currently" is.