In a revolver I usually go for just starting to flatten but not anywhere as much as the load in the middle. In a single shot however I do not crimp anything my 357 max loads are loaded to hit the lands and that's crimp enough. Mike Bellm told me not to crimp in a single shot even with H110 and w296. He's of the opinion the only reason to crimp is to prevent the bullet from moving under recoil which will never happen in a single shot.