Warning: Contains SPOILERS for The Falcon and the Winter Soldier episode 5, "Truth."

Bucky's arm is one of his key assets in terms of his superhero abilities, but The Falcon and the Winter Soldier episode 5 reveals it does have one weakness. Bucky's metal arm first appeared in the MCU when he returned in Captain America: The Winter Soldier, a replacement given to him by Hydra after he lost his real arm during the raid on Armin Zola's train in Captain America: The First Avenger. Established as an important part of his Winter Soldier persona, Bucky continued to use the arm even after healing and, having lost it in a fight with Iron Man, received an even more powerful upgrade, with a vibranium arm from Wakanda.

That vibranium appendage has become a surprisingly important talking point in The Falcon and the Winter Soldier, as the Dora Milaje revealed a failsafe had been built into it Bucky's arm, allowing them to quickly disable it (much to his shock). That itself divided fans over whether Wakanda was right or wrong to include such a failsafe, but it wasn't the end of revealing weaknesses in Bucky's arm. In Falcon & Winter Soldier episode 5, "Truth," Bucky's arm briefly malfunctions after he's thrown into some power cables by John Walker.

Related: What Ayo Said To Bucky After Removing His Arm

That's thankfully only a temporary setback, but the episode later reveals a bigger problem with Bucky's arm: it's on the wrong side of his body for it to be fully effective. When helping Sam with repairs, Bucky uses his right-hand, prompting Sam to ask him why he didn't use his metal arm. Bucky somewhat sheepishly responds: "I'm right-handed." Obviously Bucky didn't choose to lose his left-arm, and even being right-handed the vibranium arm is still incredibly powerful. But the scene with Sam does show that, even after all this time, his initial instinct is still to use his regular arm (which is, admittedly, still a super soldier arm) rather than its more powerful counterpart, which means he doesn't use the metal arm as much as he would if it were on his right side, and it's also perhaps not as strong as it would be if it were on that side.

Bucky and Sam standing next to a boat in Falcon and The Winter Soldier

This does fit with what's generally been shown in the MCU. In The First Avenger, Bucky was a skilled sniper who used his right hand as his trigger hand. When he returned in The Winter Soldier, it seems as though he'd trained to be ambidextrous, which would make sense given he was intended to be a deadly assassin, and Bucky's metal arm was one of his greatest weapons. Even then, though, he regularly holds the rifle in his right-hand. In Captain America: Civil War he switches more between the two, and in Avengers: Infinity War he briefly uses his left to hold a gun, but switches to his right for using it, and then he's right-handed in Avengers: Endgame. Likewise, the Winter Soldier's trademark knife flip is done using his right-hand as well. Even with the training he's undergone since, Bucky using his right-arm is what's most natural because it's what he did for all of his life before becoming the Winter Soldier. That's not to mention the fact that for a long time in Wakanda he didn't have a left arm at all, meaning he'd further fall back on using his right more predominantly.

Of course, even with this Bucky's arm gives him plenty of advantages - such as making it even easier for him to catch Captain America's shield. Even when training with Sam in The Falcon and the Winter Soldier episode 5, Bucky still uses his metal arm to catch it, just like he did with Steve, despite Sam not being a super soldier. The one exception to this was when John Walker used it earlier in the season, and Bucky reflexively caught it with his right-hand, once again perhaps showing his greater instinct. If Bucky's metal arm were on his right side, then it would likely make it a more destructive tool because he'd use it more, but at the same time it could be argued as a positive. If he'd just had his right arm replaced, then he might not have learned to be ambidextrous, becoming a more well-rounded fighter. Using the arm more might've been good for the Winter Soldier, but Bucky strives to leave that past behind, so he may want to use his arm less, not more, given the damage it can cause. Bucky's arm being on the wrong side was a weakness, but he can also turn it into a strength.

Next: Why Bucky's Arm Failsafe Is Dividing Marvel Fans

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