Ahhhh - the fun of regulation begins.

BTW- I didn't notice or maybe remember - did you use .308" groove diameter barrels or .310, .311, .312?

I've a friend for whom I chambered a barrel for in .303 brass, with a pilot ground to fit a .300" bore. This allows him to use 200gr. Sierra or Hornady's which was his goal, since 215gr. .303's are rare, hereabouts. He is also able to shoot .303 bullets without any aditional pressure signs as the bullet is the correct size prior to max. pressure being developed and - most importantly, due to the normal chanber neck size, there is plenty of room for up to .313" bullets. He's getting just over 2,200fps with 220's without any pressure signs in the P-17. His perfectly headspaced brass stops any flattening of the primer's radius with maximum loads.

Reading primers is a bad way to judge pressure as a tiny bit of headspace movement, .001" to .003" which is generally necessary in any single shot-type barreled action for easy closing while the firing pin hole clearance around the pin itself is the main cause of cratering.

The use of only new brass and a michrometer is the best method of pressure guessing - blade mics and extractor groove measure being the spot - both before and after at exactly the same location. If factory ammo is available, measuring just ahead of the web is a second-best method.

For those who didn't know this.