In terms of raw strength, Captain America is typically portrayed as being stronger than the Winter Soldier, although the Winter Soldier's combat skills and agility can still make him a formidable opponent.
Usually, Captain America is considered the best fighter in the Marvel Universe, but on this occasion Bucky beat him fair and square, even using Steve's own shield to deliver the final blow. The power levels of Marvel characters vary greatly according to writers' preferences and story needs.
Issue #18 of Avengers proves that Captain America's body isn't as strong as Soldier Boy's because Cap is rendered unconscious by the same gas that knocked out Hawkeye, who is basically just a regular human.
I think most of us figure Bucky and Steve are about equally matched in terms of strength, even though Bucky got the Nazi/Hydra version of the serum. But Marvel seems to put Bucky and Steve above Iron Man in terms of actual strength (super soldier vs iron man suit).
While Captain America was forced to fight the Winter Soldier a few times, Steve could never bring himself to truly hurt Bucky. There was never a true victor in these fights. In the end, Cap used a Cosmic Cube to give Bucky his memories back, and this ended their series of battles.
In the MCU, with his Winter Soldier mindset, Bucky is as strong as Captain America. If we're talking about the comics, it's because Bucky never received a version of the super soldier serum. He's still a highly trained man with a metal arm, but most of him is ordinary human.
Serum enhances the strength and ability of human. Now bucky was not weaker than John, but we can see the fact that even at his human level John walker had better training than Bucky. He was so good as fighting before even getting the serum. So he was able to fight better than bucky.
He possesses no super powers and never received a form of the Super Soldier Serum as many assume, but continues to operate at peak human ability. Winter Soldier also boasts a master knowledge of weapons and firearms. He has used a variety of guns and knives as well as Captain America's shield and even alien weaponry.
Marvel's Captain America may be the leader of the Avengers and Earth's most famous superhero, but Daredevil knows his obvious weakness - and proves he can beat Steve Rogers in a fight every time.
His Black Panther suit is weaved with vibranium that can absorb kinetic energy, such as blasts or punches, and repurpose it as a counterattack. Power scale: 7.5. Black Panther's strength and enhanced abilities are on par with those granted by Captain America's super-soldier serum.
Limited Durability: Although he is able to survive all kinds of bullets and explosions, he does have limits as Billy Butcher's heat vision is shown to be able to bisect his head despite having his superhuman durability.
The only advantage that Gotham's Knight has over Bucky Barnes is advanced technology. While Batman can use and develop any kind of technology, the Winter Soldier just likes to use his weapons. Both are pretty much equal when it comes to hand-to-hand combat.
Bucky is revived and restored by the Infinity Formula, the same chemical used on Nick Fury during World War II. This increases Bucky's vitality and physical abilities, though to a lesser degree than Steve Rogers.
The consensus seems to be that if we're just going by serum quality, Steve takes the cake (Zola's version wasn't quite as good as Erskine's formula), but Bucky's metal arm makes up the difference as far as strength is concerned.
Marvel Cinematic Universe. Bucky was injected with a counterfeit serum since Captain America's serum was not replicable, therefore, the result of Bucky's serum was bound to be lower quality.
Bucky Barnes, like Steve Rogers, has lived for several decades due to cryogenic freezing and the super-soldier serum. Bucky's life expectancy could potentially surpass Steve's 116 years, depending on circumstances.
The fact of the matter is, the arm still functions as a part of his body. The superpowered enhancements do not change the fact that he will still naturally experience pain when his body is put under such stress, especially when the arm is attached to so many nerves that could've been damaged from losing his actual arm.
Who is the strongest in Captain America the Winter Soldier?
Bucky is known to be one of the most dangerous soldiers alive. Prior to his fall, he was a sniper in Captain America's unit. Through the Winter Soldier program, Bucky received a form of the Super Soldier Serum, giving him enhanced strength, speed, and regeneration abilities.
Enhanced Strength: The Winter Soldier has strength that is equal to that of Captain America. Bucky's strength was greatly boosted by a serum given to him by HYDRA scientists. The Winter Soldier's physical strength is enhanced to superhuman levels.
Bucky and the Winter Soldier are the same person. They've technically had the same training and possess the same physical power. The only difference between the two is their mentality.
Steve Rogers, meanwhile, has greater strength of character, making him worthy to wield Mjolnir in Avengers: Endgame. He's less hampered by his own ego than John is, which makes him a stronger leader capable of inspiring loyalty and determination among his allies.
