Sad but mostly true...the bullets that have the radius olgive don't get a good enough neck tension to avoid bullet movement or set back. The bullets wit straighter side walls work much better. I will say I started with the LEE die set for the 357SIG and had two issues, first was CCI and Speer casings heve vey small primer flash holes, even the smaller pin had got stuck in the flash hole, broke off. LEE sent a replacement de-primer but new cases I now hand de-prime with homemade pin, then drill out the flash holes to the normal size of other brands. PITA but only needed once.
Second issue was worst, I had run the casings thru the 10mm carbide pass thru die before sizing in the LEE 357SIG set. The LEE dies are steel dies and even with lube the sizer die started galling and mark the cases. Just like the 9x25Dillon, I moved to the Dillon dies because of the 2 carbide sections for sizing. Yes, they are expensive but they work the best for my experience. I was lucky to find my Dillon dies on the used market for a savings over the factory price.
Sizing is critical to fit you chamber properly, no less than -0.002" below the barrel hood as primer strikes can get too light. Too much shoulder set back will lead to shorter case life or seperations. The neck expander and truing is critical to bullet being straight and holding tight. The Dillon die set doesn't come with an expander but I use the LEE expander or my RCBS 9mm expander for this operation. The Dillon set does have a seater die with double ended seater for TC & Round Nose profiles as does the seperate crimp die.
Good luck with your adventure!
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