Jay: when I first entered the 10 ring all my brass was fired in a stock G20. I don't recall ever getting a bad smiley but the brass did all have a slight bulge near the rim. My 550 sizing die when screwed just about all the way down, while not able to remove the entire bulge, has resized most rounds enough that they fit in Dillons 10mm gauge. I do not recall having any feeding issues in the G20. I recently purchased a KKM barrel for proper support. Then I fell in love with a Tanfoglio Witness Limited 10mm and I'm having some of the feeding issues that your having with the flat nose of the FMJ sticking on the feed ramp. BTW: I remember the owner of KKM asking me what bullets I use because my answer might require him to modify the feed ramp. When I said Precision Delta he said nothing else was required. Until recently I was loading all my 10mm close to 1.260. When a few rounds FTL in the Witness I figured it was the OAL but last weekend when I was chronoing several loads I had it happen on the 1.253 OAL. All future loads are going to be between 1.244 - 1.250.
Thanks for the tip on the Redding sizing die.