I use 110 or 120grit brown alum oxide - virgin. It does smooth the factory Remington finish down a bit, this was a former SPS CM action, the rings were coated as well:
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Might be a bit flat for your tastes...........

Always use virgin media and dedicate your blast media/tank to degreased rifle parts only. You don not want contamination (oils) in your media.

MtnHtr