As long as you properly maintain them, no difference. As Yoteslayer said, the stainless is susceptible to galling, especially with a really tight raceway/bolt body fit. But you will deal with rust on a poorly maintained carbon action. If your going to Cerakote it, go with a Carbon because the parkerizing will take the Cerakote better. If your going to leave it bare, go stainless. Other than that, either one when properly maintained will last a long time.