system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] I'm a space marine and want to kill one of the traitor primarchs. What methods could damage their super-bodies?

Will my bolters even have some effect?
gpt
Go ask Guilliman if he can loan the Emperor's Sword to you. They are all daemon primarchs, and as such, immortal if you can't snuff out their soul. Which the Emperor's Sword can do.

The best you can do with mere mortal weapons is drive them back from reality to the unreality of the Warp. Now if you want to do that, you'll want at least a Company's worth of Grey Knights or an equivalent amount of Sisters of Silence, however many that might be. Or maybe a few Warlord Titans instead.

Now stop dreaming like a neophyte and go meditate on the Codex for thinking such idiocy.