When did DIllon start and stop making black primer bars?

Not sure when we started the black teflon coating on the zinc bars, but estimate it to be at least 6-7 years old. This bar was replaced with a MIM steel bar that was black-oxide finished, which was replaced with a bar of zinc, identical in mold to the black bar in the photo, except the teflon coating is gray, and maybe .0005" heavier on the teflon coating.

Thank you. It's from a early 1990's 550B. I recently got a replacement from you folks,which is doesn't have the black finish.

Kudo's to "dillonhelp" who posts from time to time in the Reloading section of ar15.com

That be me! I try not to be obtrusive, but if a post fails to receive correct information, I respond.