I had a partial case head separation using a 1.8oz buffer

[Sovereign77]

Resolution is a bit lower (approximate resolution is 733 psi), as the strain gage is mounted over the bore forward of case mouth, but used factory loadings to establish max pressure limits (used Federal GM 130gr factory load as max). If I were to get it over the case body resolution would be much better. I now believe the primary root cause is the feeding cone/bolt interaction, causing excess unsupported space near case head. I do think hornady case web helps mitigate the issue, but doesn’t change the OOS bolt condition. It's worth noting that the case head dimensions of virgin hornady (and found in the hornady manual) are different (.438") than other brass manufacturers. Lapua (new brass), I've found is right around .440". I find that factory loads or reloads, the case head expands initially, but in properly machined barrels is limited and springback threshold is maintained.

I haven’t seen the bulge since but that’s because I’ve used different barrels with personally matched bolts. Going to contact Shilen and discuss.

I’ve wired up several barrels and have achieved similar responses. Interestingly, in my 24” brnls barrel, CFE223 started showing secondary pressure waves with 123gr bullets in cold weather only… but that’s a discussion for another day.