Does anyone know what type of finish the factory used on the 870's aluminum trigger guard?
I had assumed they were anodized and sent one out for type III anodizing. The results were very poor. Came out a milky gray instead of black. The gentleman who did the work reported back that the trigger material is a casting alloy which is why it didn't anodize properly.
I would typically just cerakote a part like this, but the gun has a lot of engraving and the customer is looking to match the original factory finish.

YEARS (crap almost 40 yrs now) ago when I was doing Blueing work I tried to Anodize the guard. Ended up with simply using Rust-o-leum stain black paint. Or, and the blessing of the customer buy a new guard. I always wondered if factory was anodized or powder coated.

Thanks Paul. The trigger guard has been engraved so I'm hoping to duplicate the factory finish. If all else fails I'll have to cerakote, but I don't think that will look as nice.

They were hard black anodized.