Birchwood Casey Presto Mag Liquid Gun Blue 3 Ounce Plastic Bottle Key Features Cold blue formulation that works on all steel (except stainless steel) For complete reblue applications Formulated for deep blue luster Details Presto mag gun blue is a cold blue formulation that works on all steel (except stainless steel). Specifically formulated for when you want a deep blue luster on your firearm’s metal surfaces.
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