Yo! :v/
A Haki enhanced version of Gomu Gomu no Jet Bullet. After entering Gear Second, Luffy uses Busoshoku Haki to harden his arm entering in Gear Second Busō. He then stretches it back like Gomu Gomu no Bullet. When cocked back, his arm ignites, releasing a stream of fire. When the attack hits, it creates a fiery explosion and deals immense damage!!!

See you again soon :v/