Are Major Force and Bombshell actually similarly powered to Captain Atom or are they just aping his style to appear tougher than they are. Cause to my knowledge they haven't actually matched up to him. What's actually legitimately known about them?
Neither of them MATCH UP to him certainly. Captain Atom is one of the all time greats when it comes to this generation of superheroes, he's been a leader in both loose and literal senses on multiple occasions and forth multiple teams. And indeed he's considered one of the out and out strongest of the heroes like him. Not just in ability but also in character. Despite stumbling back toward the dark multiple times he has always returned to the light and found himself stronger for the struggle every time.
But as for being "related", the answer is yes. They all more or less have the same origin. A VERY poorly thought out government experiment now declassified under the name Project Quantum.
(An image of Captain Atom and Major Force duking it out high in the air. One of many such clashes between the two men)
Discovering what seemed to be the corpse of a large metallic alien (they thought it was a spaceship) in the Nevada desert in the late 1960s, Project Quantum was the experiment tasked with studying the alien's strange chrome skin and finding some military use for its properties. After all this was the height of the Cold War. Finding that the skin seemed to be able to tap into an otherwise totally unknown energy field (now called the Quantum Field), as well as protecting anything behind the metal itself from the acute radiation effects brought on by exposure to said energy. As well as being able to absorb and redirect nearly all other forms of energy tested upon it, up to an including nuclear radiation.
Seeking to weaponize the metal but not knowing for certain if a human subject would survive the process they decided to offer pardons to military prisoners (that is, those who had been convicted at a court martial, not POWs) who volunteered. Encasing them in what was basically an egg of the material and then DETONATING A NUCLEAR BOMB UNDERNEATH. The heat, pressure and radiation would basically seal the metal over the skin of the subject while absorbing the overwhelming energy flow and turning the flesh and bone beneath into a living conduit for this unknown quantum energy. It also had the small side effect of bouncing the subject several decades into the future through the Quantum Field so both of the original times they tried it they thought the subjects had been vaporized. Those subjects of course being the men we now know as Captain Atom and Major Force. Although the operative difference between the men is that Nathaniel Adam was a good man, framed for a crime he didn't commit and forced into the experiment with the alternative being an execution at the man who turned out to be mostly responsible. Clifford Zmeck on the other hand was an out and out psychopath with a long record of not only murder and torture but also sexual assault and rape who had to be implanted with explosives underneath his metallic skin to basically be turned into a living weapon. Both men appearing in the present day of course making them much harder to control after nearly 4 decades of difference between the Project Quantum of now and then losing access to their methods of control and a big chunk of their leverage.
Bombshell was a more modern attempt at the project. Once it became clear that Captain Atom and Major Force HADN'T in fact been vaporized in the late 60s. They even managed to iron out the kink so she didn't get sucked into the future to pop out in 2050. The problem is they still thought using military prisoners as test subjects was a good plan and that ended up exactly how you think it would. The woman known as Bombshell ended up in prison after nearly getting the Teen Titans killed because she's a traitor and a liability and is currently being allowed to continue assisting them on an entirely provisional basis as part of her debt to society.
All in all, between the three of them, I still say that getting Captain Atom out of it was worth it. For all of us at least. They should still stop trying again though.
