I will never use Peterson brass for my 300norma mag again.The minimum chamber length on the CIP 300 Norma drawing is 2.502"
The maximum case length is 2.492"
The recommended case trim to length is generally 0.010" under the maximum case length. That would be 2.482"
There isn't a SAAMI specification for the 300 Norma.
I'm having the same trouble with the Peterson brass others have reported. It is .006" to 0.014" shorter than my Manson 300 Norma Go Gauge. Norma was .004"-.006" shorter, which is pretty typical for new brass.