The Wylde chamber creates a bit lower pressure than the .223 chamber with like loads. SAAMI pressure limit is 55k psi for the .223. Most agree that 65k is genuinely safe in a modern action but no one except Western Powders (Accurate and Ramshot) publish data over 55k. Western publishes data to 63,250 psi IIRC. The other option is to get ahold of Quickload and model it all up to see what you can do within 63k or so.
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