h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Regarding rifles:
Regarding manual-action repeating rifles (those that hold several rounds, and require the user to operate a mechanism before they can fire again), as well as bolt-action rifles there are lever-action and pump-action rifles, which use different mechanisms to achieve the same effect. Lever-action rifles are faster firing than bolt rifles, but less accurate. Manual action rifles are more accurate than semi-automatic ones, as in the former the mechanism does not operate until after the shot has fired, while in the latter it operates as it fires, and any vibration etc that takes place while the bullet is travelling down the barrel will spoil the accuracy.

You can also get single-shot rifles, that need to be reloaded (a new cartridge placed in the chamber) by hand after each shot (I used such a rifle when I was a member of my University's Rifle Club).


Regarding Assault Rifles:
A vital characteristic of Assault Rifles is that they are "select fire" weapons, meaning that they can switch between firing single shots on the one hand, and burst and/or fully automatic fire on the other. In combat, soldiers will normally use them in single-shot mode, as except in special circumstances, full-auto fire is less accurate, and allows you to miss faster.

Another important characteristic is that they use intermediate power cartridges, such as 5.56x45mm NATO. (Equivalent weapons using full-power cartridges, such as 7.62x51mm, have been used in the past, but not at present, as the recoil tends to be too much to use them in full-auto mode, and the ammunition is bulkier, meaning soldiers cannot carry as much. I am not quite sure what the appropriate term for such rifles is; I have seen them described as "Battle Rifles" and "Automatic Rifles", although I have also seen those names used for other weapons).

For the sake of clarity, you might want to mention "Assault Weapons", which is a rather arbitrary term used in American law to describe some self-loading (semi-automatic) rifles that look like assault rifles, but aren't.

Regarding machineguns:
Machineguns use the same sort of ammunition as rifles, but it is not really correct to describe them as "essentially rifles, but designed to fire on a fully-automatic basis", due to various differences in design and use (in particular suppressing fire rather than single precise shots). "Light machineguns" are defined as those that use intermediate rifle cartridges (as assault rifles), and "Medium Machineguns" use full-bore cartridges. "Heavy Machineguns" are those using larger calibre ammo, such as .50BMG ("Browning Machine Gun"). Automatic weapons with a calibre of 20mm or more are termed "automatic cannons” rather than machine guns.


Regarding SMGs:
Although in practical terms you are correct in saying they bridge the gap between machine pistols and assault rifles, in terms of development history, assault rifles bridge the gap between SMGs and traditional rifles. SMGs were developed for trench fighting etc, where traditional rifles were too long and too slow firing to be useful, but were found to be too weak and short range for most combat.

Incidentally, the differences you give between "Sub machinegun" and "Machine pistol" are correct in the English-speaking world. In some other languages, "Machine Pistol" is used for any automatic weapon using pistol cartridges (hence the "MP" in "MP5").


Regarding the ammunition:
Your description of the blasting cap (also: "primer") in the rear is correct for "centre-fire" cartridges, which make up the bulk of most ammunition. There is another type called "rimfire", e.g. .22LR ("Long Rifle"), where the primer is in the rim round the back edge of the case. Centre-fire cartridges can be reused (the primer is replaced, and new gunpowder and a new bullet is put in); rimfire cartridges cannot. They also tend to be less powerful.

Also, it's not really correct to say that it is the cartridge that "does the killing". Quite apart from any "guns don't kill, people kill" political arguments, it would be the bullet that does it, not the cartridge, unless the cartridge (and the gun) somehow blew up and killed the user.


Regarding the firing pin:
It is not just "assault" weapons that use this mechanism. Many hunting and target-shooting rifles do too, as (I think) some pistols.


I hope that is some useful information for you. (I got/confirmed some of it from Wikipedia, although there is no plagiarism/direct quotes).

I hope to take this article out of Flea Market and get it into the Edited Guide. Please see: F48874?thread=8290116 for the Peer Review thread for the new version.

<BB<