Originally Posted by
bigbulls
I am not defining anything.
SAAMI defines what the MAP is for each cartridge not me.
SAAMI defines that a 40, 9mm and .357 all have a MAP of 35,000psi.
SAAMI also defines that a 9mm+p load operates at 38,500 psi.
SAAMI does not define a pressure for a 40+p nor a 9mm+p+.
All +p loadings are above MAP set for a standard loading. A proof load is 130% of the standard load. This is what is determined to be the limit of the cartridge. SAAMI only lists +pressure loads for a few cartridges but for the few that it does... a +p load is 10% above what is set for a standard load. As there is no official +p+ load all one can do is guess that is somewhere between a +p load and a proof load. Probably 15-20% above a standard load.
How do you know what each cartridge operates at?
Do you have access to test barrels and a piezo equipment?
This is correct. All 38 special loads are at lower chamber pressures than 357 magnum loads.
Here is a short list of the more popular cartridge pressures as set by SAAMI.
http://www.leverguns.com/articles/saami_pressures.htm
You are "defining" as it is quite clear we are using the terminology differently (hence different definitions).
A gun designed for standard, say, 9mm ammunition is rated for 35k. +P ammuntion should not be used in these guns. There are therefore not "high pressure" rounds because in a gun designed for +p ammunition the round can handle much higher pressure. Standard and +p ammunition, by definition, reach different pressure threshholds and the standard ammo is not "high pressure" (by my definition).
A .40 is designed for 35k and, while I do not have test barrels and associated electronics, those that rate factory ammunition and write reloading manuals do. Standard .40 ammo is typically loaded up near this and therefore uses the full spec pressure of the gun -- "high pressure" by my definition. If you are "+p" in a .40, despite there being no standard definition of this, what you are saying is that the ammo is beyond the design specification of the firearm.
Standard 9mm and 38 loads do not approach the rating of modern guns, so they are not "high pressure". Standard .40 loads do so they are "high pressure". Hope that makes sense to you.