Rifles in the UK
Introduction
FIREARMS AND SAFETY
Hearing protection
How a rifle cartridge works
Recoil
Which rifle calibre?
Bullet types
Rimfire cartridges
Magazine loading
Barrels and barrel making
Reloading ammunition
Case trimming
Target marking
Deer stalking
Glossary of shooting terms
A-C D-F G-I J-L M-O P-R S-U V-X Y-Z
Automatic - Automatic is a mode of weapon operation that means the weapon will fire cartridges continuously as long the trigger is held in and there is ammunition in the magazine (or belt). The first cartridge is loaded manually and as the trigger is held, the sequence is: fire cartridge, eject spent case, load next round, fire, eject spent case etc until the ammunition is depleted. Automatic weapon are totally prohibited to civilians in the UK.
BC - Standing for 'Ballistic Coefficient', BC is a measure of how aerodynamic a bullet is. A bullet with a high BC will generally fly faster and flatter than one with a lower BC. This is a slightly simplified explanation as BC actually varies with distance and velocity. In general, short, fat bullets will tend to have a lower BC than longer, narrower ones.
Berdan Primer - A berdan primer consists of only one part, the cup. The anvil against which the primer is crushed is part of the cartridge case. Because of this design, berdan primered cases are very difficult to reload, especially as they rarely have a single, central flash hole.
Boxer Primer - A boxer primer is one that is made of two parts, the cup and the anvil. Because of the anvil design, there is a single, centred flash hole in the case. This makes the cases easy to reload because the primer can be pushed out from inside the case with a narrow metal rod and new one inserted ready for re-use.
BP - Standing for Black Powder, BP is a popular shooting discipline that usually involves manually reloading the rifle or revolver with powder, a wad and a lead ball or bullet. A separate license is needed to keep and store genuine black powder but Pyrodex and 777 are two popular modern alternatives that have no special storage or licensing requirements.
Cannelure - The cannelure is the groove around a bullet. It is usually the cannelure that the very end of the case is crimped into to make the bullet head more secure in the case, usually in military applications where repeated heavy recoil could otherwise cause the bullets in the cartridges to recede into the cases.
Centrefire - A centrefire cartridge is one that uses a primer located in the centre of the end of the cartridge case. Centrefire cartridges can be reloaded by removing this primer and replacing it with a new one. Examples of centrefire calibres are the .308 Winchester rifle cartridge and the .357 Magnum handgun cartridge.
C.O.A.L. - Standing for Cartridge Over-All Length, this is a basic measure of cartridge sizing, especially when reloading ammunition. It simply refers to the entire length of the cartridge, from the tip of the bullet to the base.
Crown - If you look at the muzzle end of a rifle barrel, the crown is the name given to the minute chamfer machined around the opening of the bore. The crown must be extremely accurately ground or machined and be symmetrical to ensure that the blast of gas that emerges behind the bullet is equally symmetrical and doesn't push the bullet off course.
CUP - Standing for Copper Units of Pressure, CUP is a long standing method of measuring chamber pressure in rifle and pistol cartridges. It works by using a special 'crusher' gun. When the cartridge is fired, a piston compresses a carefully calibrated and sized copper slug. Measuring the deformation of the copper slug against a reference standard reveals the chamber pressure.
Direct Impingement - An operating method for cycling the action of a semi-automatic or automatic firearm that does not use a connecting, or operating, rod or piston. Instead, the gas from the port in the barrel is fed directly back into the action to operate it. One example of a rifle that uses the direct-impingement method of operation is the AR15.
Double base - A double base propellant powder consists of the usual nitrocellulose propellant with the addition of a certain proportion of nitroglycerine. This gives the powder more energy and they are often sold as 'high energy' smokeless propellants. One such powder is the Vihtavuori N5** series.
Free floated - Free floating is the process where the forend of the stock is designed, or altered, so that the rifle barrel does not touch it at all. This is thought to improve accuracy by removing any external factors that could affect the barrel's vibration or harmonics.
Follower - The follower is the top plate visible in an unloaded magazine. It is pushed further and further down as the bullets are inserted and follows them back up as the rifle is fired.
Foot Pounds Energy - Foot Pounds Energy (FPE) is the measure of bullet energy favoured by the British, Americans and Canadians. The formula to calculate FPE is:

Mass (in grains) x Velocity2 (in feet per second) divided by 450240 ie. 100 grain bullet at 3,000 FPS: 100 x 3,0002/450240 = 1,999 Foot Pounds Energy.
Grain - The grain is the unit of measurement used by the British, Americans and Canadians to measure the weight of bullets and propellant powder. One pound is equivalent to 7,000 grains and 1 gram is equivalent to 15.432 grains. The term grain is also used as volume measurement for measuring quantities of black powder.
Gralloch - the gralloch, or gralloching, is the correct term for the removal of the lungs and intestines of a deer when it has been shot. It is usually done as soon as the deer has been shot and must be done carefully to avoid contaminating the meat.
Grooves - The grooves are the channels in a barrel that lie between the lands. Ideally, the diameter of a bullet should be the same or slightly smaller than the diameter of a circle that fits around the bottom of the grooves.
Joule - Joule is a European measure of bullet energy used in preference to the Foot Pounds Energy method favoured by the British. To convert Foot Pounds Energy to joules, multiply by 1.3558. To convert joules to Foot Pounds Energy, divide by 1.3558.
Lands - The lands are the protruding ridges in a gun barrel. Their function is to bite into the bullet's jacket and impart spin as it travels down the barrel.
Leade - Leade is the correct term for the throat of a barrel. When a cartridge is loaded into a barrel, there is a short length of the barrel before the lands start that is smooth. This area allows the bullet to enter the barrel, it engages the lands as moves past the leade. The leade tends to be long in commercial and military rifles to allow the use of a variety of bullet lengths and types. In target and bench rest rifles, the leade tends to be shorter to allow the bullet to be seated to a very specific depth and distance into or away from the lands.
Lock time - This is the time taken from the moment the trigger is pulled to the primer in the cartridge igniting. The quicker this is, in theory, the more accurately a rifle can be shot because it will be less influenced by the rifle barrel moving around. Lock-time is influenced by the design of the trigger and firing mechanism.
Matériel - From the French word 'matériel' meaning equipment or hardware, matériel is used describe the equipment or supplies necessary to persecute warfare. Rounds or guns described as anti-matériel may be used to destroy vehicles, buildings, improvised explosive devices or enemy supplies etc.
Mexican match - Mexican match ammo is an 'informal' term used for ammunition made up from cheap milsurp ammo that has had the heads removed, the powder charges evened out and proper match bullets seated to replace the original military ones.
Meplat - Meplat is the name given to the flat area at the front of a bullet. It can be tiny; pointed full metal jacket bullets actually have a tiny flat area at the front. On the other hand it can be quite distinct. Lead pistol and target rounds often have a large meplat to help them punch a distinct, neat hole in the target.
Milsurp - Milsurp is simply a contraction of the term military surplus. It generally refers to cheap, military FMJ rounds that are alot cheaper than modern factory ammo ie £20/100 rather than £20/20. Obviously, milsurp ammo is only available in military calibres such as .303 British, 7.62x51mm, 5.56x45mm and 7.62x39mm amongst others. Milsurp ammo is usually Berdan primered so cannot be reloaded.
MOA - Standing for 'Minutes Of Arc', MOA is used as a measure of accuracy and 1 MOA represents one sixtieth of one degree. One MOA equates to approximately one inch at one hundred yards so if a rifle is said to shoot 'sub-MOA' it is capable of placing all it's bullets in a circle approximately one inch across at 100 yds or in a six inch circle at 600 yds etc.
On the paper - This is a term to describe sighting in a new rifle and is normally done indoors on a club range at 25- or 50 metres. It simply involves getting the shot fairly central on an A4 target the idea being to at least have the rifle hit the target when shooting at normal rifle ranges. This can save alot of time and frustration.
Picatinny rail - The Picatinny rail is a standardised mounting system used on some firearms to mounts scopes, torches, lasers and other accessories. It was designed by the Picatinny Arsenal in the USA and is officially known as MIL-STD-1913 in the USA and STANAG 2324 in NATO. It is form roughly like a wide T in cross section and has horizontal slots machined into it. It can from an integral part of the weapon or can be attached as an option. The slots, which are standardised at 0.206" wide, spaced at .394" and 0.118" deep, are milled crosswise to allow expansion and contraction lengthwise without distortion.
POA - Standing for Point Of Aim. POA simply refers to the point on the target that the shooter was aiming at when he/she was shooting.
Reloading - This refers to the process of using new or spent cases to make one's own centrefire rifle or handgun ammunition. The old primer is removed from the case, the neck of the case is tightened, a new primer seated, the case reloaded with a pre-measured amount of powder and a new bullet seated in the case. Also known as home loading.
RFD - Standing for Registered Firearms Dealer, an RFD is the next step up from holding a Firearm Certificate. An RFD has no limits on ammunition or firearms that he can hold. RFDs are the backbone of the British shooting industry as they are the only people who can commercially sell new and used firearms and ammunition. They are also useful as they are enable people to post guns to each other via their local RFDs, they can also store firearms for people if necessary.
Rimfire - A rimfire is a type of cartridge that doesn't use a central primer. The priming compound is spread around the inside of the rim of the case. The rim is struck by the firing pin which discharges the cartridge. Because they don't use a central primer, rimfire cartridges are not reloadable. Example of rimfire cartridges are the .22 Long Rifle and the .17 Hornady Magnum Rimfire.
Section 1 - Section 1 of the 1968 Firearms Act basically deals with anything you could class as a firearm and thus require Police permission to acquire ie anything requiring an FAC.
SAAMI - Standing for the Sporting Arms and Ammunition Manufacturer's Institute, SAAMI was formed at the behest of the American government in 1926 to be an umbrella organisation responsible for setting and monitoring standards and safety in the firearms industry. SAAMI is perhaps best known for controlling chamber design and firing pressures in firearms. SAAMI is an accredited standards setter for the American National Standards Institute (ANSI).
Section 2 - Section 2 of the 1968 Firearms Act basically deals with anything you could class as a Shotgun and thus require Police permission to acquire ie anything requiring a shotgun certificate, or SGC.
Section 5 - Section 5 refers to firearms and ammunition that are generally prohibited UNLESS you are granted special permission to acquire and own them. Section five covers things such as handguns and rocket launchers etc but in a rifle shooting situation, it most commonly refers to expanding ammunition that requires Police permission to buy ie for stalking or pest control. It also applied to semi-auto or pump-action shotguns that hold more than 2 cartridges. Reasons for ownership of such shotguns may be for professional pigeon control or practical shotgun competitions, both of which require alot of cartridges to be loaded at once.
Sectional density - This refers to the relationship between the frontal area of a bullet and it's mass. The heavier a bullet is for any given calibre, the higher it's sectional density will be as the frontal area stays the same but the weight increases. Bullets with a high sectional density are said to offer excellent penetration of targets.
Semi-automatic - Semi-automatic refers to a rifle or handgun that, once cocked, reloads itself when fired, without the intervention of the shooter. The mechanism works by either utilising the energy of the empty casing being blown backwards, or by diverting a portion of the pressurised gas behind the bullet, to eject the spent case when the gun is fired and load the next round. The gun is fired by repeatedly pulling the trigger with no need to manually load the next round between shots. Also referred to as 'self-loading'.
Single base - Single base is the term used to describe 'standard' smokeless propellant powder. It is made mainly of nitrocellulose. An example of single base powder is the Vihtavuori N1** series.
Straight-pull - Straight-pull can refer to certain types of bolt-action rifles where the bolt handle does not need to be lifted before it is pulled back or lowered when the bolt is fully forward. It is more normally used in the context of semi-automatic rifles that have been made in single-shot mode for the UK market. The gas port is disabled and each round must be loaded manually by pulling back and releasing the cocking- or charging-handle. Two popular examples are the AK-47/74 and the AR15.
Throat - Throat is a common term for 'leade'.
Twist rate - Twist rate refers to the rifling in the barrel. The barrel has a series of raised ridges ('lands') that the bullet engages causing it to spin. Twist rate refers to how many inches of barrel it takes to turn the bullet around one complete revolution ie a 1-in-8 twist will rotate the bullet completely every 8 inches it travels down the barrel. The longer a bullet it is, the faster it must spin to stabilise so in general, for a given calibre a faster twist is needed to stabilise heavier bullets.

The speed a bullet will be spinning at when it leaves the barrel can be calculated with the following formula:

Speed in FPS x 720 divided by twist rate ie my .223 fires a bullet at 3,200 FPS and has a 1-in-8 twist so (3,200*720)/8=288,000 RPM
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