Sydney's 10mm "Ultra" SMG

is used by the relic hunter Sydney.

My little Moonbeam
Sydney the relic hunter carries this weapon. It can be obtained by either killing her (no bad karma), letting her die, or finishing the quest Stealing Independence and giving her the A Note from Little Moonbeam's Father. It can also be looted from her by pick-pocketing, waiting for her to die, or killing her yourself.

"A Note from Little Moonbeam's Father" is located within the ruins of the hotel in the quest Reilly's Rangers. During the mission, be sure to check the side rooms until you find a skeleton on one of the beds. You'll find an assault rifle under the bed, some ammo next to it, and the voice tape on the bed next to or under the corpse. Go back to Sydney after finding it in Rivet City and she will tell you it was from her father, that he was attempting to make one big deal and set her up for life, but was double crossed. Realizing she was wrong about her father, she will give you the gun. Note however that this can only be done AFTER returning the Declaration to Washington. After speaking to her in Rivet City, she will move to Underworld and become a weapons merchant there.

Bugs/Exploits
There is a bug/exploit in all versions of Fallout 3 that allows you to receive multiple copies of her Ultra SMG in perfect condition (along with 50 rounds of 10mm ammo). To trigger the exploit, after receiving the gun once choose the following dialogue options:

"Since we're done now, why don't you tell me about yourself?" "Nice gun. I've never seen one like that." (she mentions her father and re-triggers the option to ask about him)

"That's all for now, I guess" (taking you back one step in the dialogue tree)

"So, whatever happened to your father?"

and finally, "Sydney, I found a note from your father. He didn't abandon you."

You should then receive the Ultra SMG and ammo again. The above steps can be repeated as many times as you want for a limitless supply of both guns and 10mm ammo.

One bug that was found by an Xbox 360 player. When visiting Underworld's 9th Circle bar Sydney was found dead on the floor, complete with armor, her "Super SMG" and ammo. It is unknown why she was killed, by whom, or by what means.

Sometimes, if you already completed Stealing Independence and later on found the recording, you can still show her to get her unique gun. She tells you she's heading to Underworld. However, when you get there you'll find her ammo stash in the 9th Circle bar but she won't be there. Check the Anacostia station entrance almost directly north of the Rivet City entrance. Go into the tunnels and she'll still be there, JUST starting her journey. You can escort her if you like, the walk isn't that long at all. (Had this happen on 360 after finishing the quest with her as well.)

YouTube Videos
Obtaining Sydney's 10mm "Ultra" SMG R4tyj7G8Lo8

Weapons Lists
10-мм ПП Ультра Сидни