Personal weapons: Personal weapons come in two primary categories; projectile (autoguns and bolters) or energy (lasers and plasma guns). Most personal weapons are made from advanced light alloys, synthetics, and composite materials. They are lightweight and highly durable, but most importantly they are cheap and easy to mass-produce. Personal weapons come with fixed sights, but commonly have some form of improved targeting gear – rangefinders, optical sights (with or without targeting enhancement), vision enhancement (light-enhancement and/or infrared). Many weapons are auto-stabilized and/or incorporate recoil dampeners.

Almost all weapons have some sort of built-in processor that takes care of a variety of tasks not readily detectable by the user – keeping track of ammunition, warning about jams, overheating and other failures, keeping various aiming aids working at optimum performance, tuning lasers to optimum wavelengths, possibly priming ammunition, working automated feeding/clearing systems, ensuring maximum stability for auto-stabilized weapons, and a host of other things.

Projectile weapons: By far the most common personal firearm in the Imperium is the good old slug-thrower, a weapon that has been around - quite literally – for 40.000 years. Slug-throwers come in a million different variations, but the basic principle is the same; impart kinetic energy to a smallish and dense object, and have it rip apart whatever it hits.

Slug-throwers range from primitive muzzle-loaders found on some feudal worlds, via simple black-powder guns on worlds with slightly more advanced tech-bases, to the ultra-efficient modern weapons available on most Imperial worlds. Some semi-archaic models utilize cased ammunition, cartridges and such, but most contemporary Imperial weapons are autoguns firing high-velocity case-less rounds using an electic pulse for igniting the propellant.

Even more advanced models utilize magnetic accelerators to propel the bullet, adding bulk but also giving higher muzzle velocities. The Adeptus Mechanicus and a few other tech-guilds have the ability to manufacture slug-throwers using grav-pulse technology for truly incredible projectile velocities, but these weapons are very rare, extremely expensive, and ill-understood (Eldar weapons are typically of this type, albeit far more elegant and efficient).

There is also a bewildering array of ammunition types, ranging from primitive lead ball, via basic mantled bullets, to exotic adamantine-tipped mass-reactive explosive projectiles. The most common type of projectile is a saboted kinetic heavy core penetrator that has decent penetrating capability and good damage characteristics against flesh. Other common ammunition types include incendiary, incapacitating, explosive, and armor-piercing types.

Autoguns/autopistols: Autoguns are full-scale rifle-type or squad-support weapons intended for military use, while autopistols range in size from true pistols to light rifles intended for high-risk security work. The autogun is a favorite with many PDFs and paramilitary groups, mostly because they are extremely cheap and easy to manufacture, use and maintain. The autopistol is a common sight among enforcer cadres, Arbites, private security forces, and gangers. Autoweapons are not typically found in the hands of ordinary civilians.

Both types of weapon are capable of a very high rate of fire, using case-less ammunition and (typically) the pulse-ignition system. The main difference between autoguns and autopistols is caliber/muzzle velocity. Autopistols fire relatively small projectiles (typically 3.5 mm) at lower speeds, and thus have reduced range, penetration and damage compared to autogun ammunition (typically 5 mm for rifles and light support weapons and 7 mm for heavier support weapons).

Heavier versions of the autogun are sometimes referred to as autocannon, but such weapons are more correctly classified as heavy weapons. They must either be tripod- mounted and have 2-3 man crews or be mounted on vehicles for use against massed soft targets, light vehicles, or other semi-hardened targets. Autocannon fire masses of high-caliber (typically 15-30 mm) projectiles at impressive muzzle velocities.

Bolters: Bolters are a type of slug-thrower that deserves particular mention; they are the weapon of choice of the legendary Adeptus Astartes – the Space Marines (and they are also a favorite choice for veteran Ork warriors). Instead of launching an inert projectile they fire miniature self-propelled projectiles. This gives bolter longer range and better penetration against distant targets when compared to ordinary projectile weapons. Initial launch from the bolt gun is accomplished through any of the methods mentioned aove; case-less pulse technology for Imperial (and Ork for that matter) bolt weapons, with Astartes weapons always always employing a gauss-type accelearator.

The main drawback of bolters is bulk and weight. To be effective the missiles launched have to be fairly massive, resulting in a very heavy weapon with a large high-caliber ammunition (.75 cal is standard) and a bulky gauss launch system. While this is no problem for Astartes in power armor to heft a 40+ pound weapon system the same cannot be said for normal humans. Lighter bolters use the weaker .50 cal ammunition and a simpler pulse-ignition system, but the weapons are still characterized by great bulk and limited ammunition capacity. Though less effective than Marine bolters, the Imperial bolter its still a potent weapon system and does see use with some Stromtrooper divisions and other elite formations.

Bolt pistols also exist; they fire the same caliber (.75 for Astartes weapons and typically .50 for 'civilian' versions) ammunition that bolters do, but the rounds have a much smaller initial charge (and less capable gauss-type launch system) to reduce both recoil and ammunition/weapon weight. Bolt pistols thus have less accuracy, range and penetrating power, but if they do penetrate they can do nearly as much damage as a full bolter rounds. Apart from being the back-up weapon of choice of the Astartes, bolt pistols remain fairly rare because of their weight, recoil, difficulty of use, and high ammunition cost. But in the hands of a skilled operator they can be very deadly indeed.

Heavy bolters fire the incredibly potent 1''/25 mm round that combines excellent range, superb penetration and lethal damage in one small package. It can deal effectively with everything from power-armored infantry, to masses of unarmored targets, to light-to-medium vehicles. The heavy bolter is the Astartes support weapon of choice, but it also sees some use with special forces units, and it is a common secondary weapon for vehicles and aircraft. The assault cannon is a special heavy bolter with an astounding rate of fire that is employed almost exclusively by Space Marine Terminators.

Needlers: Needlers or needle guns (also known as sliver guns) are semi-common weapons in the 41st Millennium. Needlers fire low-caliber ammunition at modest velocities. It is not a military weapons system since its range and penetrating power is limited, but primarily see use with assassins and certain other civilian organizations. The selling characteristic of needlers is their ability to fire silently and accurately. Several types of ammunition exist, ranging from super-dense penetrators, via molecularily destabilized darts (contact-explosive), to toxic-crystal (a favorite of assassins). Basic Imperial needlers use a powerful spring mechanism to launch the needle at speeds just below the sound barrier. There is no thermal bloom, no muzzle flash, and very little sound produced. A small power cell resets the spring after each shot, giving needlers a decent rate of fire. Needle rifles are quite rare since they defeat the purpose of the needler; keeping a low profile. Still, some snipers and assassins favor the needle rifle for the lack of muzzle flash, thermal bloom and other side-effects common to standard projectile or energy weapons. Some needle rifles have a selector to allow them fire supersonic darts for better accuracy at long range.

Eldar marauders frequently make use of a somewhat similar weapon system (often called 'splinter rifles'), although it uses a laser beam instead of a spring system to propel the needles. Similar STC-compliant weapons are available in the Imperium, but while they have a better rate of fire and more power than spring-needlers, they are no more stealthy than normal lasweapons. Regardless of origin this variety of needlers fire crystal slivers that can – depending on the power setting of the lasbeam and the ammunition use – kill, injure or just deliver whatever toxin is infused in the toxin-crystal-matrix ammunition. Eldar commonly use on low-power setting to incapacitate and capture unarmored targets.

Gauss autoguns are sometimes called needlers (because they fire needle-like projectiles with narrow cross-sections, much like needlers do), but they are a different breed of weapon altogether, being advanced high-power autoguns manufactured for military use. The same applies to various grav-pulse projectile weapons employed by the Eldar (including the iconic 'shuriken catapult)' and other 'advanced' (but degenerate) xenos races.

Launchers: Launchers are weapons designed to fire grenades or missiles further than an ordinary soldier can throw the same ordnance. Many grenade launchers are man-portable, shoulder-fired weapons, usually mounted on a rifle-type weapon such as a bolter, lasgun or autogun. Such launchers are frequently single-shot, but certain patterns have magazines, typically with space for 3-5 grenades (plus one in the launch tube). Independent launcher systems exist, such as the Imperial Guard SGL (Squad Grenade Launcher). These weapons will almost invariably have either box or drum magazines with room for a large number of grenades. Unlike the rifle-mounted systems these weapons are capable of semi-automatic, or even full-automatic fire. Grenade launchers are also used as heavy support weapons or mounted on vehicles, ether as an offensive weapon system or as a defensive measure (launching smoke/blind or frag grenades against close-in infantry).

Standard ammunition for grenade launcher is the 30-40 mm high-explosive grenade, but special grenades are also available. These range for non-lethal webber rounds, via auxiliary types like flare, smoke and blind, to krak greandes and melta designed to deal with armored targets. Many ammunition types are primed by the launcher's machine spirit as it is fired; for example, frag rounds can be set to explode at a certain distance or elevation, thus enabling them to affect hard-to-reach targets.

Missile launchers are scaled-up versions of the grenade launcher, capable of firing larger projectiles with more capable payloads over longer distances. More primitive missile launchers can be of the single-shot type, but most have magazines and are capable of semi-automatic fire. Too heavy for ordinary soldiers to carry, they must either be operated by 2-3 man fire-teams, be emplaced, or carried by power-armored Astartes (together with heavy bolters missile launchers are the primary support weapon for Space Marine squads).

Shotguns: Shotguns of the 41st Millennium have little in common with the hunting weapons of earlier ages, but rather combines the characteristics of autoguns and bolters. They are capable of semi-automatic to fully-automatic fire with large caliber (.75 being quite typical) ammunition of various kinds. Shotguns are very effective at shorter ranges (they lack the muzzle velocity and penetrating power of true bolters, and do not have the accuracy or rate of fire of autoguns), especially against lightly armored targets, making them popular with enforcers and starship security alike (because the chance of damaging ship-critical systems is reduced).

Standard shotgun ammunition consists of dense-penetrator flechettes that can punch through light armor and deliver terribly wounds to unarmored targets. Other ammunition types include self-propelled (a cheap version of the bolter), high explosive, incendiary, stun, entangle, and many more. Several common shotgun patterns (such as the Lathes Pattern Arbites Riot Gun) have two (or more) magazines spaces, allowing the gunner to switch between several ammunition types at the flick of a switch.

Stubbers: The term 'stubber' is a catchall for the myriad less advanced projectile weapons manufactured and used throughout the Imperium. They exist in a wide range of size and complexity, from small two-shot hold-out pistols, via large caliber revolvers and semi-automatic pistols, to machine pistols, various rifles made for hunting and war, to light and heavy support weapons.

The selling points of stubbers is their simplicity and low-tech nature. They can be manufactured anywhere there is even a small industrial base. Because of their cheapness and ease of use they are found in great numbers even on worlds with a high tech-base. Getting a license to carry a stub pistol is fairly easy; indeed, getting caught with an illegal stub revolver might result in just a period of incarceration, while having a military grade weapon on you could lead to far worse.

Stubber ammunition is usually just as simple as the weapons themselves, cheap and low-tech, but exceptions do exist. The same goes for accessories; most stubbers lack anything beyond fixed sights, but if you've got the Thrones for it you can add things like advanced sights to your stubber.