Explain +P Ammo

They have more power. Some weapons, usually old ones, cant handle the extra pressure. There is also a +P+ that was a police load. I still have a few boxes.

Kevin
 
The ammunition industry group, SAAMI, sets chamber pressure standards for cartridges and usually goes very much to the safety side of the equation. For example, the .38 Special cartridge is over 100 years old, and certain firearms which were chambered for it in 1900 might not be able to handle the pressures that a more modern firearm might (better metallurgy, for example). In the case of a few cartridges like the .38 Special and 9mm Parabellum, they set additional standards for those firearms which are SPECIFICALLY designated by their manufacturers to fire +P ammunition. These firearms are usually marked +P on barrels or frames and are also so noted in the manual that comes with them. One should only fire +P ammunition in those firearms specifically designated for it by the manufacturer.

As far as I currently know, +P+ ammunition is supposedly only available to law enforcement and the military, but I could be wrong.
 
Most commercial ammo is loaded to SAMMI specifications. SAMMI determines the maximum pressure allowed for each caliber. For older calibers such as .45acp, 9x19 and .38 special (among others) SAMMI also has a “+P” rating, which allows higher peak pressures that the round was originally allowed for modern guns that can handle the extra pressures. In general ammo with +p ratings have higher velocities with the same bullet weights than their not +p counterpart. This is not always true. It is the integral (area under the pressure curve) that determine velocity. This is why Doubletap Ammo can load the .45acp within normal SAMMI ratings and still exceed the velocities of other manufactures using “+P” pressures.

Since there are no established pressure ratings for +p+, the ammo manufactures determine what they think is safe.
 
Thanks for the information! In a previous post I inquired about the quality of a Charter Arms .38 spl. The manufacturer claims that their .38 can fire +P ammo, but "not a steady diet" of them. Conversley, the S&W airweight can regularly handle the +P ammo.
 
My understanding is that the old loads from the '40s and '50s were considerably hotter than what is loaded today. The Buffalo Bore loads are some attempt to get back to what the original specs of .38spc and .357mag were. In the '70s and '80s the loads were downgraded severely owing to, you guessed it, legal issues.
 
The handbooks used to publish loads that were well above the current +P ratings. You could usually shoot these without damage to the gun- at least for a while.

The first Airweight Chiefs were not rated for any firing of +P ammunition. It seems that the more current ones are and that some changes have been made to them to make them stronger. At least the Titanium and Scandium ones are supposed to be stronger than the ones that were made a few years ago.
 
Current factory +P (P is for pressure, BTW) are not all that hot and are much weaker than older high performance loadings.

I would avoid +P in an alloy gun. My opinion.
 
357 mag tuarus titanium

I was thinking about getting a 357 mag titanuim taurus. This will handle 38 special + p no problem right as it is lower power than a 357 mag? it is a lite weight and small gun.
 
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