Question about "Over Pressure"

[Jordan Smith]

Yes, but if your brass does not allow 5 reloads without loose primer pockets, your load is higher pressure than what that brass can support!
Prematurely loose primer pockets = extreme pressure (for those cases) every time!

Absolutely. The danger shows up at the other end of the spectrum. If you have some hard, resilient brass, you may be running dangerous pressures before you get much case head expansion!

 

[Jordan Smith]

Some guns are stronger than others but the case is the weak link. When it lets go, it can get messy.

I have fired hundreds of thousdands of rounds through piezoelectric pressure guns, copper and lead crusher guns and even a strain guage on my Remington 7400.

By the time you get a sticky bolt or a shiny ejector mark you are probably at or beyond proof round pressures.

There are significant variations of "identical" barrels and chambers and even bigger variations between different source barrels. The laod developed in your buddy's rifle means nothing.

But ther is no free lunch with velocity. If the book says max is 2700 with 4895, then you had better stop at 2700 with 4895.

Amen!

 

[thecollector]

and we both agreed that Tikka make some super strong actions !

Firearms fabricators conform to engineering standard practices of building a safety factor of twice the working pressure to burst pressure for the barrel/action (known reliable materials operating under known conditions).
For example a typical high power rifle to handle a 60,000 psi load would be fabricated from an AISI 4340 Chromium-Molybdenum low alloy steel quenched & temperd (heat treated) to a level of around 120,000 psi tensile yeild strength, which renders a machine capeable of repeatedly operating within its elastic limits with a significant margin of safety remaining. This represents an optimal strength level for the application, AISI 4340 can be heat treated up to double this tensile yeild strength level, 240,000 psi, but at that level the material is quite brittle and apt to shatter like glass when subjected to impact loading such as in discharge of a cartridge.