Need advice with cratered primers vs pressure issues

[willienels]

I need some advice about cratered primers and pressure. Am developing a load for a Weatherby Vanguard .270 Win using Hornady V-max 110 gr, IMR4831, CCI 200 standard LR primers, and once-fired/partially FL sized RP cases. Shot yesterday one each 58 gr, 59 gr, 60 gr. The 58 gr showed no external evidence of excess pressure. The 59 gr showed only a tiny bit of primer cratering, no flattening, no resistance to bolt lift. The 60 gr showed a little more cratering, but otherwise was same as 59. The cratering in both cases can be felt when dragging a pointed awl across the ridge.

My policy has always been to stop short of any cratering, but in this case most of my data sources list 60 gr as max. Also, all my sources used standard LR primers as opposed to magnum LR.

Any advice about how to proceed will be appreciated.

Bill

 

[mdi]

I believe primers are unreliable for pressure indicators. Too many variables that would show up as flattened or cratered primers (along with deciding "how much" flattening/cratering). If I were approaching max. loads I think I would pay attention to extraction and head expansion...

 

[gamestalker]

Primers are not reliable to read pressures off of. Look for ejector imprint on the case head and feel for resistence when opening the bolt. And if you see any radical change in the primer, such as being excessively flattened out to the edges of the pocket that woudl qualify as semi reliable. And of course if you start punching holes in primers, and it's not your FP causing the failure, your pressures are deffinitely high. And also if the primers fall out of the case head upon ejection, seen that happen a time or two.