Often, Naruto would still be one of the main characters. Since it's in the Naruto universe, he'd be likely to interact with the chakra gun in some way, either trying to master it or facing an enemy who wields it.
I'm not sure if there are extremely famous 'naruto chakra gun' fanfics. But it's possible that in the vast sea of Naruto fanfics, there are some that have gained a following due to this unique concept. Some fans might be really drawn to the idea of a chakra gun and so might promote or share those fanfics more often. You could also check Naruto - related forums to see if anyone has recommended such fanfics.
In Naruto fanfic, a 'chakra gun' could be a creative interpretation. It might be a weapon that utilizes chakra in a unique way, perhaps concentrating and projecting it like a gun. It could be a device created by a fanfic author to add an interesting and new combat element to the Naruto universe.
Well, one interesting concept could be the unique way the chakra gun is designed. It might combine the traditional chakra usage in Naruto with a new form of weaponry. Maybe it has different levels of power depending on the user's own chakra reserves and control.
One interesting concept could be a character unlocking the hidden potential of the chakra gates in a unique way. For example, they might discover a new sequence of opening the gates that gives them powers beyond what was thought possible in the original Naruto lore.
One consequence could be that he becomes extremely powerful. His physical abilities like strength, speed, and endurance are enhanced. He can also use more powerful jutsus with the extra chakra boost from the Kyuubi.
One interesting way is when Naruto absorbs chakra through his shadow clones. In some fanfictions, the clones can be used not just to gather information or attack, but also to absorb the chakra of the opponents they interact with. Then, they transfer this absorbed chakra back to Naruto, making him more powerful.
Perhaps there is an ancient artifact or a powerful curse that causes Naruto to absorb all chakra. In the fanfiction world, it's common to introduce such unique elements. For example, he might find a magical scroll that, when opened, starts sucking in all the chakra in the vicinity and then channels it into Naruto. Or it could be a curse placed on him by an enemy, but instead of harming him, it gives him this strange power to absorb all chakra.
The consequence might also be a shift in the balance of power in the Naruto universe. With all that chakra, Naruto could potentially change the political situation. He could end wars single - handedly or force the different ninja villages to re - evaluate their strategies. Moreover, his own physical and mental state might be affected. There could be a struggle within him to keep his identity intact while dealing with such an overwhelming power source.
He could share it with Hinata. Given their relationship, Naruto might transfer some of his chakra to Hinata to protect her during a dangerous situation. This would also strengthen their bond further in the fanfiction.