Had a 300 WM blow primers with charges 2.0gr below max set at the recommended OAL. I found in that rifle starting charges were shooting about 150 fps faster than the book estimated them at. I never take shortcuts now. I start at the minimum charge and work up.I would advocate staying afraid of going past max in the newer rounds that actually publish real max. My 6.5 CM was maxed out, leaking or blowing primers more than a grain below max. Published COAL helps but even still that 62k-63k psi wall is pretty firm. Older cartridges in newer guns? stuff em good.