I've had hit or miss luck with factory blems, as you would expect. 6.5 nosler rdf's worked great, the 6mm rdf's not so much. And 6.5 Hornady 123 eldm's from midsouth shot great.
I shoot Blem 300 smk .338 and 175 smk .30 and Nosler 140, 6.5 cm with out issue. From what i could tell it was just jacket discoloration was the reason they were Blem's
I started ordering 285gr ELD blems whenever I can. I cannot tell a difference other than the box they come in and the color of the copper jacket. They measure and shoot just as good for me for the batches I have gotten them in over the last couple of years. Keep an eye on the price as it will fluctuate widely on them from midway. The price will hold steady for a while then jump up and drop even lower then ever. This is all assuming they are not selling as fast as midway would like.