[@Lmpkio]
You vastly underestimate Space Marines.

If this fight is going to play out, you need a concept of why 40K is considered bullshit OP by most. I'm going to quickly detail what makes Space Marines utterly unstoppable.

In order to join the Space Marines, you need to be an unstoppable badass. Only elites of the likes of Snake or Shepherd even get into the program. For example, in order to join the Space Wolves, you need to kill a giant wolf monster the size of a car with nothing but your bare hands. And that's BEFORE they get superpowers. In order to join the Salamanders, you need to kill a giant firebreathing dragon on an active volcano using a weapon you built yourself. The Dark Angels initiation is a secret, but it's known that in the old days you needed to kill a giant chaos monster using only mediëval weapons and armour. That gets you initiated as a Scout Marine - not even a full Space Marine.

If you were to take an AK-47, place it against a space marine's forehead and pull the trigger, the bullets would bounce off his skull. Without any armour, space marines are capable of withstanding machine-gun fire with relative ease, and have enough strength to bench press a car. They live for almost a Thousand years, and are incredibly skilled. And that's without any special gear.