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?