The web, ie: thinning of the case where expansion to seal the chamber starts, is usally around 3/8" up the case in all cases, rimmed, belted and rimless, not just the 6.5x54. This location is easily seen by merely looking at a fired case or measuring it with a mic or calipers. A micrometer will give more accurate measurements than calipers will provide.

I allow NO expansion of the solid head of the case. I have read that up to .001" expansion is OK, however I prefer '0' expansion of that part of the case. Any expansion there, loosens the primer pocket. This 'loosness' is immediately felt when repriming the case and sometimes when poking out the old primer, depending on your method of that.

To properly measure case head expansion, one needs to mark the case prior to firing it - and measure those marks - fire the ctg. then re-measure on those marks. That is the ONLY way of discerning an accurate measurement. When a mere thousandth is the maximum allowed, calipers are NOT the tool to use. You must use a mic that is capable of measuring and being read to the 1/10,000".

I already noted that overpansion of the web area is indicative of an overly large chamber, NOT an indication of pressure.

From a post above.

"Overly large diameter expansion at the web is caused by an oversized chamber, not by excessive pressure nor excessive headspace. You must find out first, what the problem is - oversize chamber at the head, or a bonified headspace problem."