I would mic the casehead if there are questions concering overpressure. Flattened primers on their own do not automatically indicate overpressure. if you don't have a mic, use the sharp edges of your dial calipers .200" above the case rim. You will of course need a dimension for comparison from cases that are in spec, from factory ammo, or cases you have resized. The reloading manuals list the spec diameter of .391", so don't be shocked if yours are a couple thousandths smaller. Most everything I run into these days seems to be slightly smaller than spec dimension in length and diameter!