Does anyone know how the factories get that smooth matte finish on natural (i.e., uncoated) stainless steel firearms?

It’s got to be blasting with some kind of abrasive, but what do they use?

Ive used just plain blasting beads on Muzzle brakes. I turn the air pressure way down just enough to remove the shine from the stainless. Comes out pretty close to factory

i've TRIED pillow/sugar sand - NOT a good idea, but it sure was "matte"

glass beads, would be a good way to start a new box of beads, and get them broken down for finer finishes --

Earl makes a good point, for these finishes, rather than cleaning (i grew up sand blasting since I was 10 in my dad's company laydown yard), air flow/volume down, material up, making an inefficient cone that does more "polish" than "strip"

I have used soda but not baking soda. You have to get it from media dealers but it leaves a nice satin sheen.

Don't overlook Jeff' comment about "braking down"the beads. I've used the same beads for maybe three years ..morre like flour now.

Depending on pressure/ position you can have almost a non reflective polish.

Thanks. Just picked up some fine #10 glass beads and will give them a try. Slow and low to start!

you want, to start, a stream that almost looks like mist, with HEAVY bead flow -- the beads break when hitting the metal, so, yeah, the finish gets finer the more you use it --

turn up the air till it bit A LITTLE

Ditto used beads comments to get a finer finish. Also pressure and distance from metal surface influence texture. You can also "groom" the blasted finish with a SS carding wheel. That's how we duplicate the Browning factory finish.