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CCI SR primers are not meant to be used in 223 or 556 loads as they are meant for the 22 Hornet class of cases. Otherwise 46K psi max. That is why they flatten and pierce. They are thinner than all other primers. Use Win SR and don't worry about any of this.
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GONRA (as mentioned by others above) suggests CCI Military primers (small rifle and large rifle) for all semiautos.
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i load 26g H335, 55fmjbt (both new and gi pulls) and cci primers at 2.245 OAL in mixed brass, for all of mine, my sons 2 and 2 buddys ARs. with the eotech on my 16" olympic, i can hit the 4" steel plate at 100 all day long offhand, the dot almost covers the whole plate