There are a few types of Pirates that could have a good advantage on a Space Marine: Assault Shield Troopers, Assault Aerotroopers, Pirate Commandos, and Pirate Commanders.
The Assault Pirate Troopers are some of the best the pirate military has to offer. They are heavily armored and are resistant to most attacks. Their unique armor will deflect all Missile fire, but is still damaged by Beam attacks. Basic armament includes an assault rifle and energy scythe, both powered by Phazon. EMP grenades are often employed against power-armored foes. A new Dash Jet system provides increased mobility.
Assault Shield Troopers are heavily armored and resistant to most weapon systems. Their unique armor will deflect Missile attacks, but not Beam fire. In addition to their armor, they wield a portable battle shield. Their battle shield provides protection against all standard weapon fire, but can be easily torn off. Phazon-based weapons are capable of destroying the shield
An Assault Shield Trooper is, in all likelyhood, immune to bolter fire. The armor is designed with slopes that simply deflect missiles, rerouting them into the sky or ground. Their shield will reflect beam fire and plasma and, because it's an energy based shield, will become much stronger in Hypermode. I forget if EMPs will do anything to Space Pirates, but anything vaguely electrical likely won't survive it. Anyway, I believe a Space Marine would have to go into melee to even hit the Pirate. They are armed with what are basically lightsabers, but I'm positive any given Space Marine would tear a Pirate to pieces in melee.
Only the best can join the ranks of the Assault Aerotroopers. Heavily armored, they are resistant to most weapon systems. Their unique armor is able to deflect all Missile attacks, but can still be damaged by Beam weapons. Like regular Aerotroopers, they wield two Remote Attack Pods in combat. One is equipped with a Particle Cannon, the other with a Gel Bomb Rack. Gel Bombs stick to their targets until detonation. High-velocity movement can remove Gel Bombs.
This is basically an Assault Trooper, except it can fly. Still immune to missile fire, but doesn't have a shield to reflect beams. It removes melee from the equation, but puts plasma back in. In Hyper Mode, however, they can still take a ridiculous amount of damage. Plus, it'll try to kamikazee if it dies, and attempt to pull a draw.
I can't find the Commando scan, but they have a personal teleportation system and a cloaking device.That's in addition to their assault rifles, energy scythes, dash jets, and EMP grenades. They are not immune to missiles, but have a ton of health that only increases in Hyper Mode.
Commanders make heavy use of their personal teleporter, moving to favorable positions and across the battlefield, giving orders and support as needed. They carry all of the weaponry and gear used by commandos, with the exception of their armor, which is forged out of ultrarare Red Phazite. A rare breed, Pirate Commanders have lived to rise to the ruling caste on the Pirate Homeworld. Each has been a commando for at least ten years.
This guy is just annoying with his constant teleport spam. He's got the cloak, the scythe, the assault rifle, and the EMP, as well. The worst thing about him is that Red Phazite, which is near indestuctible. Not immune to missiles, either, but a truly awe inspiring amount of health. Samus has to repeatedly blast him in her own Hyper Mode for several minutes to remove the armor. His basic strategy is to teleport around and take potshots before teleporting again.
These are just the Pirates I reccommend against a Space Marine. It's by no means all of them. There are other varieties that are near immune to beam weapons, but are vulnerable to missiles, for example. Or those that just don't wear armor and are basically cannon fodder.
I like you. I'm a Metroid fan myself, sir. 😛 I've played all the games except for Metroid II for gameboy. You don't need to find my scans, I have most of the basic knowledge memorised from my three or four play throughs of the prime trilogy. 😛
That said, I'm reasonably certain a bolter would be equivelant to missile spam, for example. Bolters are incredibly powerful weapons, not wholly ineffective against 40K tanks. (though not particularly effective, either.)
Comparing dstructive feats, the SA-X's super missile can damage and partially collapse a hallway in a space station made of an unidentified metal. We don't have a feat for her normal missiles, unfortunately.
A bolter shell is designed to peirce armoured targets, and is tipped with diamantine. It then explodes with enough force to rip apart a man in ceramite power armour.
I think it'd work fine on your typical pirate's armour, some exceptions exist, but a named space marine such as Tarkus, Avitus, Cyrus, or Thaddeus is going to be carrying more than just a bolter. Thaddeus is probably the second most dangerous to a pirate, next to the force commander himself, due to his melee orientation and his jump pack.
But like I said, this is all speculation until we know what the thread is actually about. 😆
It could even be v.s. a starcraft marine.
Hyper mode would be an interesting twist, to say the least, if this is a 40K marine.