Is the only difference between them cosmetic, or does the teflon actually do anything on the inside to improve reliability?

Thanks for your time!

Considering they're about the same money and look a damn sight better, especially in the long run, it's teflon only for me.  The teflon finish is slick, the dry film is rough, common sense would say the teflon would lend itself to an edge in reliability.  But lots of folks use the dry film mags with no issues.  So who knows?

I haven't noticed a dif in performance with either. I can't poo-poo teflon considering that I coat all of my mil-spec mags with Dura-Coat or Norrels. Basically I'm doing the same thing. The black teflon looks good though.

Both have a non-abrasivve finish as the Moly Coat used on USGI Mags is actually a luricant for Metal on Metal engagements, but not suited for many of these cycles because it wears off easily. Remember that USGI Mags with their Dry Moly coating were designed to be a "Use once and throw it away" part. FWIW....Many folks spray their mag springs with it as well for extra lubricity inside the mag body.

To your question...The Teflon mag finish just holds up better than the Dry Moly USGI Finish. It only takes 10 or so insertion/ extractions and the Dry Moly is gone at the point where the Mag Catch rubs on the side of the Mag.

Not so with the Teflon finish. My Teflon Mag that's always in the gun has been inserted/ extracted at least 200 times with no signs of wear.

As far as "Functionality" and "Reliability" goes....IMHO it's a toss up.

YMMV

Tack