When Jiraiya used Rasengan on a tree, it shredded part of it and trees are not soft. They are so much harder than human flesh. However, the first time Jiraiya used it on a gangster, he didn't die.
Why is that? He should have been torn to shreds.
When Jiraiya used Rasengan on a tree, it shredded part of it and trees are not soft. They are so much harder than human flesh. However, the first time Jiraiya used it on a gangster, he didn't die.
Why is that? He should have been torn to shreds.
When the Rasengan makes impact, there are two effects that take place
The first effect is
On contact, the Rasengan grinds into its target, propels them along the Rasengan's trajectory - either away from the user or into the ground beneath them
When Jiraiya used the Rasengan against the gangsters, this what we saw.
The second effect is
and at some point bursts, causing severe damage at the point of contact.
The burst is what truly deals the damage. Jiraiya mastered the technique of the Rasengan and more than likely had control over it for it to not burst.
Anyways, he was trying to make a point and get the gangsters off of his back - there was no need to kill them. Jiraiya even says
And I was holding back. You guys are hardly worth the trouble
Naruto hasnt taken the full amount of time to gather the energy needed in order to fully hand out the highest amount of damage possible with his Rasengan. As he progresses through his practices he grows stronger because hes learning how to fully use his Rasengan. The more he learns, the easier and stronger it becomes.