Not an actual bullet, but researchers fire plenty of things at spacecraft shields to test them. Here's one I found in full Performance of Whipple shields at impact velocities above 9 km/s. They fired aluminum balls in the range of .004g to .3g at 7 to 9.9km/s.
The shield failed against .3g at 7km/s. That's 7,350J or about three times what a typical battle rifle fires (see below).
It held up against .03g at 9km/s = 800J. That's a bit more than a typical pistol round (again, see below).
Before you go concluding a spacecraft is "bulletproof" against a handgun, there's a few caveats.
That's just for the shields they tested
This particular test was comparing some new designs against a baseline shield. Different spacecraft will have different shielding. The same spacecraft will have different shielding over different areas. This just gives a ballpark estimate.
Every hit damages the shield
"Bulletproof" armor isn't. Every piece of armor has a V0 and a V50 rating. These are it's design limits to stop a certain amount of energy 100% and 50% of the time over a certain amount of rounds. Eventually it will fail.
In addition, Whipple shields are designed to take damage to reduce the energy of the impact. A thin layer of metal vaporizes on impact dispersing some of the energy of the impact. This is known as ablative armor. Hit it again in the same spot and the armor will be weakened.
With the amount of damage these shields took from single impacts, I'll bet unloading a clip of 9mm will give you at least spalling if not full penetration.
For more detail on ballistic protection, see my attempt to make Captain America's Shield feasible.
Some of the energy numbers for bullets in the question and comments are WAY out of scale. It's worthwhile to review the energies of bullets. (Note: all numbers are approximate for the typical load. The same round has all sorts of variations in bullet weight and powder load. Barrel length also maters, a shorter barrel means lower velocity means less energy.)
First, typical pistol rounds.
- 9x19mm Parabellum, the typical "nine" pistol round. 7.5 grams at .4km/s = 600J.
- .45 ACP, the famous "Colt 45". 12g at .3km/s = 600J.
Now the most powerful pistol rounds.
- .44 Magnum, "the most powerful handgun int he world" according to Dirty Harry. 16g at .4km/s = 1400J.
- .50 Action Express made famous by the Desert Eagle. 19g at .45km/s = 2000J.
As you can see, that's no where near the 8000J claimed in the question. These are a full order of magnitude below the velocity of even the low end of an expected micrometeorite strike. That translates into 100 times less energy.
Next, modern battle rifles.
- 5.56 NATO the standard western rifle round like from an M16, 4g at .9km/s = 1800J.
- 7.62x39mm used by modern Russian rifles like the AKM, 8g at .7km/s = 1600J.
- 7.62x54mmR used by the AK-47 (but not modern Russian rifles). 12g at .8km/s = 3600J.
That the 4g 5.56 NATO and 8g 7.62x39mm have nearly the same energy says a lot about how important a small boost in velocity is.
Now WWII era stuff you're not likely to see, but this is the most energetic a bullet gets without getting into specialty ammo and guns.
- .30-06, the standard US round in WWII. 12g at .8km/s = 4000J.
- .50 BMG, used by US WWII aircraft and still used today in vehicle mounted heavy machine guns. 45g at .9km/s = 19000J.
4,000J is the biggest bullet you're likely to see fired at a spacecraft... on the ground I guess, but you can go up to 20,000J. These are all moving at less than 1km/s.