Quote:
Originally Posted by Bushrat
How do you explain our SR benchrest loads with softer thinner federal primer cups not exhibiting these signs when 99% of SR benchrest shooters use loads that generate anywhere from 65,000 to 75,000+ psi far above SAAMI recommended book loads yet display none of these conventional signs of over pressure on brass, primer or present sticky bolt lift.
It is well known that judging pressure by brass appearance, primer appearance, bolt stickiness etc., is often akin to reading tea leaves. While it is an indicator to investigate the reason why this is happening it does not always reflect actual pressures or necessarily mean the load is over pressure. It is well known overpressure loads may display none of these indicators leading people to believe their load is safe when it isn't and conversely leading some to believe their load is overpressure when it isn't as illustrated in 260 Rems pictures.
|
Again I was referring to 222/223 Saami Cartridges and My 20 Wildcats built on these cases with Factory specked actions. I have reformed at least a dozen 222/223 cases, both new and fired 1X to my 20 EXTREME and 20-223 EXTREME. Actually none of the 1X fired 223 Cases exhibited any primer flow nor were they even close to being fire formed to a Saami chamber at the PR, or Base datum, indicating that they were likely well within the Saami Pressure for the 223. Primer flow may have been controlled due to a heavier firing pin in an AR so that may not be accurate in a bolt gun. However every case showed primer flow when pushing a 40 V-Max to over 3600 fps in my 20-223 CZ 527 just as they did at a similar velocity in my 20 EXTREME. None of the Cases completely fireformed to a Saami Minimum 223 chamber at the base datum. Hornady 204R Factory ammo has up to 0.004" primer flow in both 32 &40 grain offerings so I feel safe stopping at 0.002 or 0.003" protrusion. I can assure you that measuring Primers is very accurate in this situation and what I pictured is exactly as described not what someone else sees.
As far as I know the 6mm PPC that BR Shooters is not a Saami Specked cartridge. I have no experience with this cartridge but will suggest that the firing pin spring is strong enough to withstand the pressures exerted , as is the primer and case. I might ask how many firings that they get on a case but am not really that concerned about what the BR Crowd.
Elkhunter 11 accused me of suggesting that he loaded to where the bolt seizes, which again was not true if you read my post, as it is actually a quote from a notable BR Shooter. I really hope that this practice is not picked up by new loaders just as I do the "Safe in my rifle Practice".