Cannon Jump Kick
Cannon Jump Kick (キャノンジャンプキック, Cannon Jump Kick) is one of three up special moves usable by Mii Gunners in Super Smash Bros. Ultimate, being essentially a revised version of the previous game's Cannon Uppercut.
When used, the Gunner fires a concussive blast, propelling themself with the arm cannon while kicking into the air. The concussive blast can meteor smash opponents. The move can hit twice (once during the initial blast, and the other time via the Mii's leg) and is fairly strong, but as a recovery, it does not cover much distance. As a result, while its power compliments a more aggressive playstyle, much more care is needed when offstage, as the Gunner's ability to survive is noticeably lessened.
The concussive blast comes out nearly as quickly as the Gunner's jab (on frame 6, as compared to the jab on frame 5). If used on the ground, the Gunner will be intangible during that first active frame, and if the blast connects, it can, as mentioned, combo into the kick. Regardless of whether the blast connects, the kick comes out shortly thereafter (on frame 10). The attack causes helplessness and has significant landing lag (28 frames, as compared to Arm Rocket's quick 14 frames and Lunar Launch's 18 frames), so care must be used when utilizing it offensively so as not to leave oneself open to attack.
Overall, while the move is arguably worse than the Gunner's other options when viewed strictly from a recovery standpoint, this is balanced out in part by the move's attacks making the Gunner more dangerous offstage (a careless foe may find itself getting meteor smashed, for example), and more importantly by the sheer power of the move, which offers the Gunner a quick, close-ranged KO option they otherwise lack (though at higher percentages, the Gunner's tilts can be used to similar effect and with less chance of being punished). Players looking for a reliable recovery should probably consider one of the Gunner's other custom moves. However, Cannon Jump Kick should always be considered, because it is one of the best out-of-shield moves in the game. A player looking for a powerful addition to the Gunner's arsenal of attacks may consider using this move, so long as they have confidence not only in their ability to read a foe, but especially in their offstage game, since the slightest error offstage can lead to the loss of a stock (much like the Gunner's sibling character, Mii Brawler).