Magnum, +P, and +P+

What’s in a word?
A magnum small arms cased round generally means a hotter (aka more powerful charged) round than a standard round that fits the same gun. Which was basically meaningless unless you compared every type of ammunition made in that calibre to work out who was top dog of the pack.

So the ammunition makers got sophisticated and stopped using the old tired term magnum and created the term “overpressure ammunition” with a little help from SAAMI (the Sporting Arms and Ammunition Manufacturers’ Institute). It is commonly designated as +P or +P+

Which means what exactly?
+P is the old magnum. Well sort of, it pencils out at about +10% more power.
So if we take a round that delivers 100 ft.lbs at the impact, at the same range (and all things being equal) it will impact at 110 ft.lbs which pleases a small but delusional group that thinks 10% actually matters.

It sort of follows that +P+ ammo is the holy grail of the gun hoe.
Imagine a round that gives more percentage smack than a standard +P (10% more than a normal load) in the hands of someone who truly believes that SMACK is everything.

Only by what amount of extra power is +P+ to +P?
And this is where it gets really funny.
+P+ has more power than +P.
That’s it, a simple statement.
No percentage increase, just a bit more powerful than the +P (standard load + 10%) so generates a tiny bit more SMACK.

OR, to put it in simpler terms, it’s meaningless!
Both hot loads ( +P and +P+) are still less power than a proofing round which is the absolute limit of what you can put through a gun and walk away unscathed.

In real life, +P is what I’d call NATO loads.
The old 2Z version of the 9 x 19 mm round used in the Sterling SMG or Browning GP35 pistol. It fired, it ejected, and the whole cyclic operation was sort of guaranteed as it was well powerful enough to ensure full movement of the mechanism. As for 2Z improving accuracy or SMACK power?

Practically it never made a difference to me or others I knew as you keep shooting until the threat is neutralised and nine times out of ten that was down to shot placement NOT some delusional theory that more SMACK guarantees a downed target wherever the bullet lands!

Aw, have I upset the power freaks by saying that?
Shame.

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9 Responses to Magnum, +P, and +P+

  1. equippedcat says:

    From what I remember, “magnum” is a different casing so that a magnum will not fit into gun of the same caliber which is non-magnum (for safety), whereas a non-magnum round does fit into the magnum gun of the same caliber (for many good reasons). Conversely +P is more power in the same casing. In my day, I had lots of experience with .357 magnum and .38 Special, and some experience with .44 Magnum and .44 Special. The Magnum rounds were significantly more powerful then 10% over the Special rounds…

    • Yep agree except 22 magnum, same size, 7.62 (38 win), same size but had hot loads, 9 x 19, same size in military terms 1z and 2z, 38 special, a lovely round, 357 mag, too much for me to control one handed in a small revolver frame (little hands).
      I read a while ago that proofing was 95% frame tolerance. Yet I couldn’t find reference to that when looking. So std + 10% seems reasonable to me (70-80% max).

      Ultimately, to me personally, it’s all about placement and what the make up is of the bullet.
      .17 is a man stopper, in the right place, 7.62 x 54R is efficient, predicable, and controllable, 50 cal makes mincing easy i.e. too much gun for most situations.

      Shot placement.
      The difference between those who can shoot and those who prefer high capacity mags.

  2. shtfprepper says:

    I’ve never had a need to buy +P rounds. I’d rather pay for normal loads and get a few more of those bullets when compared to the price for +P’s.

  3. Rifleman III says:

    When the NYPD went to +P ammunition, suddenly, perpetrators who were shot, did not get up again, and dropped to the pavement, a whole lot quicker.

    New York City had a prohibition against magnum ammunition, as the politics were such that they only wanted to “hurt” and not kill (go figure?), and the Federal Bureau of Investigation came up with the beautiful gem of +P+ ammunition for federal agencies operating within the city, as the cases were still marked as .38 Special. When the cat was let out of the bag, the criminal supporting City Council, demanded the +P+ be banned from the city.

    The FBI got around that dilema with unmarked cases other than .38 Special, and were not to be obtained anywhere except from the federal ranges. I got about 300 rounds, due to being very active and had numerous hooks. It was virtually .357 ammunition. I could not carry that on duty nor off duty, because if the ammunition was anything except regulation Winchester 158 grain Lead Semi-Wad Cutter +P, indemnification would be void. Fortunately for myself, I followed the regulations, and all three of my On Duty shootings were covered.

    Around 1996/1997, something strange took place, and suddenly, the Ballistics Section, could not identify service weapons that fired projectiles. The regulation service ammunition had been modified at the factory. The lead was a tad softer, because the City, requested it. With the +P loading, the powder charge, when fired through a 4-inch barrel, suddenly lined the barrel with lead, fouling it, and the projectile, was so clean of tool marks, there was nothing except indication of rifling marks from the barrel. At that time, there were about 29,000 police officers in the city, and there was a run on ammunition, cleaning out the equipment section, the gun range section, and every gun shop in the city and all counties touching the city. Cops, stocked up on the stuff. The City, then demanded a change to previously harder lead. Right around that time, the 9mm service weapons were issued.

    • Interesting history lesson, thanks for that.

      Lead Semi-Wad Cutter. A sensible shaped CQ round. Transferring much more energy than a FMJ.

      Only you’re right about lead shaving. A touch of antimony and Pb goes hard. Without that smearing and chamber throat and rifling build up can be a nightmare.

      One of the beauties of casting your own was “smear control”.

      Sat here now remembering scalded fingers using boiling water through the barrel and then jagging it with Hopps to clean the gunk from the barrel?

      Argh! “Pass the butter love”, was a once a week ritual years ago.

  4. gamegetterII says:

    Reblogged this on Starvin Larry and commented:
    Great explanation.

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