Sorry, had a brain fart and thought we were talking 28 ga rather than 410! I'm definitely getting old!
Much the same can be said for the 410 except they are even less common than 28 ga. What little I have seen was Fiocchi and it's been awhile. I think Scheels a month ago was the last place I've seen them.
With regards to Cheddite primers and Browning firing pins, my experience is the bottom barrels have much greater piercing issues than the upper. I've taken to using Cheddites in the upper barrel for single shots like trap or skeet and load the bottom barrel with a different brand primer when I may need to shoot twice. It is a little hassle but I've been able to get at least 3-4 years out of my firing pins rather than yearly (or more) replacement shooting Cheddites in the lower barrel.
