What does the "+P" mean on the side of ammunition boxes?

Question

What's the idea behind the whole "+ pressure" thing?

Answer 1

The +P means the cartridge is loaded to a higher pressure than standard SAAMI specs for that cartridge.

These are "carry" loads, meant for stopping something/someone in their tracks. The additional pressure caused by more powder or a more potent powder, equates to more velocity, hence more stopping power.

Not all firearms can take these loads safely - only modern firearms in good condition and those for which the manufacturer states +P ammunition is acceptable, should be fired with +P ammunition. If used often, they will cause excess wear on the firearm (not to mention they are expensive), so its advisable that once you fire some to get used to them, you keep the rest for when you are in a defensive situation.

Answer 2

Inserts from the Wikipedia Encyclopedia

Overpressure ammunition, commonly designated as +P or +P+, is Small arms ammunition that has been loaded to a higher internal pressure than is standard for ammunition of its caliber, but less than the pressures generated by a Proof round. This is done typically to produce rounds with a higher muzzle velocity and Stopping power, such as ammunition used for defensive purposes. Because of this, +P ammunition is found in handgun calibers which might be used for defensive purposes.

The +P+ designation is not currently used by the SAAMI, but is used by some manufacturers to designate loads that exceed the +P SAAMI specification.
One source lists the 9 x 19 mm +P+ loading as having a pressure of 42,000 psi, an 18% increase over the standard pressure of 35,000 psi, and the .38 Special +P+ as 22,000, a 29% increase over the standard pressure.

Unless the firearm is explicitly marked as being +P rated or it is clearly stated in the gun's manual, +P ammunition should not be used. If in doubt, a check by a gunsmith or a phone call to the gun's manufacturer will verify the safety of +P ammunition in a particular firearm. Ammunition that is loaded to +P pressures is clearly marked on the headstamp as such, usually in the form "9mm Luger +P".

Link attached




http://en.wikipedia.org/wiki/%2BP

This is the best explanation that I have seen, so I pass it on to you.
This is just inserts there is a lot more on the link you might wont to read.

Hope this was of some help.
D58

Answer 3

These are increased velocity loads that some heavy firearms can handle. You would need to know i f the manufacturer recommends this ammo, or not. The +P is about 200 fps faster with the accompanying increase in pressure and recoil. Its generally a custom, Colt does not recommend this ammo. The use is for heavy custom 1911 frames and custom barrels-high performance handguns that shoot the .38 Super at above-industry standards.

Answer 4

It means the round is loaded to higher pressure. Its more of a marketing ploy, makes very little difference for on target proformance weather thats a paper target, aminal, or human.

What it does do is excellerate wear on the gun, louder report, increased recoil and muzzle flash.

Answer 5

Ammunition Supply Rates

The overriding issue during the time frame January-June 1966, (more important than the port thru-put of ammunition which will be addressed later) was that of determining valid supple rates. The supply rates had far-reaching implications in that they impact on the length of time D to P stocks, would last. (D to P stocks are those war reserves of ammunition which are stocked in peace time to provide the necessary reservoir of ammunition to sustain combat operations until such time that the planned production base can be activated and producing at a rate which equals consumption. The designation "D" signifies deployment date or the date that hostilities commence and "P" signifies production day, hence D-P stocks.

Answer 6

plus powder

Answer 7

They were to lazy to write( extra ) full story