Re: Which brass for 300 win mag.
I make no claim of being a professional, but I ran into the same issue with Winchester brass availability and ended up trying Norma brass which has been readily available from Sinclairs. It's more expensive, but I really like the brass. I'm up to 10 reloads with an annealing every 4-5 loadings with no signs of stress or loose primer pockets. The total case capacity of the Norma brass measured with Retumbo is 2.3 grains higher than the Winchester brass, and the case body above the belt is .001-002" larger. Headspace of new brass is identical, as is the wall thickness at the neck. The Norma primer pockets are a very tight fit with Fed215 primers. I use 79gr of Retumbo with Berger 210 VLD's to get 2880FPS out of my 26" Milspec Rem 700, ES 6, and sub .5MOA- 5 shot groups. Hope this helps.
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