Inside Mama Dolce's factory. The factory is full of Chinese remnant soldiers and virtually all carry this weapon. You should be able to obtain most (if not all) of them here, making the hunt very short.
Pronto's shop will have a better inventory and he will also get a bit more caps (around 400 instead of around 150).
There are pictures on the right with a typical before and after inventory list. Largely what is gained the store is turned into a "typical good gun and ammunition store" (of which there already are several of in the game) with an additional 20% discount. Use this to determine if you feel this quest is worth doing, since there is no other reward.
If you have begun this quest and wish to complete it, do not become hostile with anyone in Paradise Falls. While the doctor will still offer services, Pronto does become hostile towards you, making it impossible to complete the quest.
Pronto does not care about the condition of the rifles, so it is advised to resist wasting caps on rifles or repairs. Because of this, however, a good way to get rifles is to shoot them out of the hands of those carrying them.
After you have given him the 20 Chinese assault rifles, you have to wait at least 24 hours before his inventory improves.
Pronto will not accept the Xuanlong assault rifle, so players using the weapon need not worry about accidentally giving it away.