As to the feed ramp, my point was that it should never be "GLOBBED" with lube. Feed ramp issues are generally fixed by a good (manual, not mechanical) feed ramp polish. You are not trying to take off metal, just buff it up a bit. S&W CS has asked me to do that on my Shield, so if done gently, no, it does not void the warranty. If you whale into it with a Dremmel, that's another story.
And mags generally do not need lube. That only provides an attractant for dirt and gunk to jam up the follower. Yes, cleaning with a lightly oiled rag is good, but then follow with a clean one to take off any excess. Oil on a mag is only for storage, as I see it.
As to ammo, when I've had issues with extraction / double feed, the test CS suggested to me is to use 124g FMJ or NATO (often listed as 123g) FMJ. If there is a problem with that, send it back to CS.
And mags generally do not need lube. That only provides an attractant for dirt and gunk to jam up the follower. Yes, cleaning with a lightly oiled rag is good, but then follow with a clean one to take off any excess. Oil on a mag is only for storage, as I see it.
As to ammo, when I've had issues with extraction / double feed, the test CS suggested to me is to use 124g FMJ or NATO (often listed as 123g) FMJ. If there is a problem with that, send it back to CS.