Traditionally a calibre reserved for mounted guns, aircraft and light armour, but a crazy man, from south africa made a sniper rifle that fires it.
High Explosive SP=5, P=3, AP=4
Armour Piercing SP=5, P=4, AP=4
Fragmentation SP=5, P=2, AP=3 (frag rounds have a kill radius of 10 feet from the point of impact)
SLAP SP=4, P=5, AP=5
SLAP incendiary SP=4, P=5, AP=5
Depleted Uranium- the best armour piercing munition in the world, it is incredibly dense and as such has ENORMOUS kinetic energy, it is self sharpening so when the point of the round breaks it fractures in such a way as to always leave a sharp point, so the rounds’ massive kinetic energy is always focused to a tiny point of enormous pressure, so it will slice through almost anything, including god. It is also pyrophoric, which means it burns in air under specific circumstances, those circumstances only occur during high speed collisions with things, like when its shot out of a gun, so its perfectly safe to handle as long as it hasn't been fired out of a gun and hit something. The upshot of all of this is a round that will go through any armour on the planet like a hot knife through butter, even if it is very thick, heavy armour, and, when it comes out of the other side, it will be a razor sharp burning lump of heavy metal, still travelling at enormous speeds and surrounded by a cloud of burning uranium dust and splinters, all of which burns with incredible ferocity, and will ignite anything they touch. As such, these are perfect for destroying tanks and armoured vehicles, as it negates any armour they have and kills anything inside with radioactive fire and burning heavy metal splinters and shrapnel whizzing around, in addition to igniting any munitions and fuel present blowing it up as well. SP=5, P=6, AP=6
Armour Piercing: Bullets that have a lower frangibility than soft core FMJ ball ammo and as such will hold together longer, and punch through light armour. These bullets are often solid steel or bronze, or have a solid steel core. as opposed to the soft lead core of standard ball ammo. they can punch through light body armour, some light armour, armoured glass. The effectiveness of armour piercing ammo increases with the calibre of the bullets, so 5.56mm Nato will be cack, and .50 BMG will go through most anything but armoured vehicles. however, not particularly effective at range.
Ball: standard bullet, unmodified, usually a soft lead core surrounded by a full metal jacket, often of some kind of nickel alloy. Not particularly effective against soft targets as they don’t flatten, and doesn’t add to the calibres stopping power, also not great penetration, and doesnt add to a calibres penetration as the soft bullet is ineffective against hard targets. the name derives from when muskets were used and fired musket balls or ball, and the name has stuck.
SLAP: Saboted Light Armour Penetrator, as if thats not clear as mustard, it means that this round has a small diameter high velocity tungsten penetrator, of a much smaller diameter than the cartridge, and that the gun firing it is chambered for, this makes the the bullet or “penetrator” extremely high velocity as the same amount of powder is propelling a much smaller projectile, albeit tungsten and so very dense with a hearty dose of kinetic energy at incredibly high velocity. but surely, i hear you cry, it will rattle around inside the barrel and not hit a damn thing? Aha! Says I, that is where the Sabot (remember that) comes in, it’s basically a kind of lightweight (polymer i think) sheath that surrounds the penetrator forming an airtight seal inside the barrel, allowing the expanding gases from the cartridge to push the penetrator down the center of the barrel, and imparting spin from the rifling, then when it reaches the end of the barrel, the sabot falls away, so that it doesn’t inhibit the bullet, and the penetrator can continue its merry way all on its own, at high velocity. these are very effective against body armour and light armour, with much greater armour piercing capabilities than armour piercing ammo, but pretty cack for soft tissue damage, as they pass straight through, leaving a small hole each side and a bunch of hydrostatic shock. in larger calibres (like .50 BMG) can penetrate all but heavy armour, for which you’d need depleted uranium or something.
Hollow Point: also called dum-dums, or soft tips, these are bullets that easily deform on contact, flattening, fragmenting or expanding inside the human body and increasing their surface area dramatically, this results in massive soft tissue damage, small entry wound and large exit wound, these bullets dramatically increase stopping power of smaller rounds, but are crap against hard targets. such bullets can be improvised by cutting a cross shape in the top of a flat headed FMJ ball round, or cutting indentations in the jacketing or cutting the tip off, this causes the jacketing to peel back and flatten, or expand, giving a result similar to hollow point rounds.
H&K: Heckler and Koch, German small arms manufacturer, makes everything from sidearms to sniper rifles. (USP, Mk 23, MP5, UMP, G36, G3, PSG1 etc)
Slug: colloquially a bullet, but in firearms terms a solid slug of metal fired from a shotgun, as opposed to shot.
bMagnum:[/b] a lengthened and much more powerful round, the power comes from the extra powder, and greater bullet mass. often used in revolvers as the massive power can significantly damage automatic actions, the large calibre magnum automatic pistols use special gas operated rotating bolt actions more akin to rifle mechanisms than handguns.
Sabot: Wiki Link because it's simpler than writing the thing out.
FMJ: Full Metal Jacket, a technique whereby a bullets soft lead core is covered in a jacket of nickel or steel alloys, this increases ballistic performance, and reduces wear on the gun.
[b]Single action:[/]b Has to be cocked before pulling the trigger.
Double action: can be cocked by pulling the trigger, or cocked manually for a lighter trigger pull (giving slightly more accuracy) most pistols are double action unless stated.
Bullpup: A layout for firearms whereby the action is behind the trigger group, so that the magazine, feed, breech and ejection port is located to the rear of the trigger, such as in the British SA80, french FAMAS assault rifles, or Israeli TAR-21. it is slightly more complicated to produce, especially in easily maintainable forms, however it offers a good barrel length, and hence accuracy, in a much more compact form, making the weapon much more maneuverable in confined spaces, and reducing the silhouette of people carrying it. it also results in a weapon that is much more balanced and less front heavy, allowing easier target acquisition, and making standing shots much easier.
And that's your lot. Enjoy.