Showing posts with label Lee Enfield. Show all posts
Showing posts with label Lee Enfield. Show all posts

Saturday, October 31, 2015

Cartridges Rims: Rimmed vs. Semi-Rimmed vs. Rimless vs. Belted vs. Rebated - Part III

In our last couple of posts, we looked at a few cartridge rim types: the rimmed cartridge, semi-rimmed and rimless types. We will look at a couple more rim types in today's post: the belted type and the rebated rim type.

As we noted in our previous post, the basic problem with rimmed cartridges was reliable feeding from box magazines, as the cartridge rims would interfere with each other in this type of magazine. One way to solve this was to reduce the diameter of the rim, as we saw with the semi-rimmed type of cartridge. Of course, the smaller rim made it trickier to headspace the cartridge in the chamber properly. Around the same time, another type of cartridge was introduced in 1905 to solve both issues: the belted cartridge.

The belted cartridge design originated in England and was designed by the famous sporting gun manufacturer, Holland & Holland. A belted cartridge is similar to a rimless cartridge in that the rim is around the same diameter as the cartridge case and there is an extractor groove in front of the rim for the extractor claw to fit in and pull out a spent cartridge. The belted cartridge differs in that in front of the extractor groove, there is a raised ring in front of the extractor groove.


The belt acts similar to the rim for the purpose of headspacing the cartridge in the chamber properly. This design allows smooth feeding through box magazines, but also has the advantage of providing positive headspacing, just like a rimmed design. Most belted type cartridges are designed for high-powered hunting rifles.

Headspacing on a belted cartridge. Click on the image to enlarge. Public domain image.

The origin of this type of cartridge had to do with when black powder was being replaced by smokeless powders, specifically cordite. As we saw in the linked article about cordite previously, cordite is composed of long strings of a light brown color, which are packed into a cartridge case in bundles like spaghetti. The prevailing production method of these cartridges in England consisted of inserting small bundles of cordite into a straight-walled case, which was then necked down to the final shape and the bullet was seated. Because of the long strings of cordite, cartridge cases using this propellant tend to have long sloping shoulders.

A .375 Holland & Holland magnum belted cartridge

When these cordite cartridges were first developed, most rifles were still single shot designs, so they were designed as rimmed cartridges. However, as the bolt-action rifles started to become popular, there began a demand for proper feeding from box magazines and hence, the belted cartridge was developed. The first belted cartridge was the .400/375 Holland & Holland Belted Nitro Express cartridge, and it was specifically developed to compete against the German 9.5x57mm Mannlicher-Schonauer cartridge, which was being adopted by Holland & Holland competitor in England, Westley Richards. However, soon after, a German gunmaker named Otto Bock designed the 9.3x62 mm Mauser cartridge. This cartridge was made to be fired out of the Mauser M1898 rifle, which was designed to be mass-produced and cheaper than most British rifles at that time. The cartridge and rifle rapidly became popular with African hunters, because of its all-round capability to be used against animals ranging from the smallest antelopes to the largest elephants. In response to this, Holland & Holland developed the .375 Magnum Belted cartridge in 1912. The belted design allowed cases to feed and extract reliably in the tropical environments found in India and Africa. The .375 H&H Magnum rapidly became one of the most popular all-round hunting cartridges in the world, and in many regions of the world, it is considered to be the legal minimum caliber allowed to be used to hunt large animals.

Interestingly, in the US, the belted cartridge has become synonymous with the word "magnum" and there are several calibers of belted cartridges available, such as: .257 Weatherby Magnum, .300 Weatherby Magnum, .375 Winchester Magnum, .350 Remington Magnum etc.

Rebated cartridge: In this type of cartridge, the rim of the cartridge has a noticeably smaller diameter than the body of the cartridge case. The rim is only used for extraction purposes, and proper headspacing is achieved by using the cartridge mouth or bottleneck body shape. The rationale behind this type of cartridge is to offer increased case capacity (and therefore, more power), without changing the bolt face of the weapon and thereby, keeping most of the other parts of the weapon unchanged.

For instance, in the 1980s it was desired to increase the power of police pistols which use 9x19mm parabellum cartridge. In response to this, Evan Whildin, a vice-president of Action Arms, designed the .41 Action Express cartridge.

A .41 Action Express cartridge on the left, compared to a 9x19mm Parabellum cartridge on the right.
Click on the image to enlarge. Public domain image.

The image above shows a .41 Action Express (.41 AE) cartridge on the left, compared to a 9x19 mm. Parabellum cartridge on the right. The reader will immediately notice that the cartridge on the left is fatter and longer, but what is interesting to note is that the two cartridges have the same sized rims at the bottom. In the case of the .41 AE, since the case body is fatter, the rim is actually smaller diameter than the case body.

The idea behind the .41 AE was that it allows converting a 9 mm. pistol to use this cartridge, merely by replacing the barrel, mainspring and magazine. Since it has the same sized rim as the 9x19 mm., the other parts of the pistol, such as the extractor claw, bolt, firing mechanism etc., can be reused and therefore, it keeps the total cost of converting the weapon relatively low.

However, when it was introduced, many of the ammunition manufacturers backed the .40 S&W cartridge, which had similar performance, and therefore the .41 AE cartridge didn't become popular. Nevertheless, the idea of using a rebated rim cartridge to interchange with another weapon stayed on. For instance, the .50 Action Express (.50 AE) cartridge is designed to be used with the American/Israeli Desert Eagle pistol. The rim of the .50 AE is the same diameter as the .44 Remington Magnum cartridge, which was the most common caliber cartridge used by the Desert Eagle. By interchanging only the barrel and magazine, a Desert Eagle originally designed for .44 magnum, can be used to fire the .50 AE cartridge.

Other cartridges that use a rebated rim design include Winchester Short Magnum, Remington Ultra Magnum, Winchester Super Short Magnum, Remington Short Action Ultra Magnum, the .50 Beowulf etc. The .50 Beowulf has the same sized rim as the 7.62x39mm cartridge used by AK-47 and AKM rifles and is designed to be used by modified AR-15 rifles.

Happy Halloween everyone and stay safe!


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Monday, October 26, 2015

Cartridges Rims: Rimmed vs. Semi-Rimmed vs. Rimless vs. Belted vs. Rebated - Part II

In our last post about various cartridge rim types, we looked at the rimmed cartridge. As we noted in the last post, rimmed cartridges are some of the earliest metallic cartridges developed and they work very well with revolvers and shotguns and rifles with tubular magazines, but not so well with box magazines. There are ways to work around this problem by carefully placing the cartridges in the magazine, as was done by the Lee Enfield and Mosin-Nagant rifles, which we saw in the last post, but these rifles have relatively small sized box magazines with less capacity.

Since box magazines can fit more cartridges in a smaller package than tubular magazines or revolvers, by the end of the 19th century, more and more weapons (especially military weapons) began to feature them and with increasing magazine capacities as well. Therefore, the cartridge rim type needed to be fixed to work well with larger capacity box magazines. There were two different cartridge rim types that were developed to fix this issue:
  1. Semi-rimmed type
  2. Rimless type
Semi-rimmed cartridge: This was one of the first attempts to fix the issue with rimmed cartridges and box magazines. The diameter of the rim is slightly larger than the case diameter, but only marginally so. 

Click on the image to enlarge. Public domain image.

The rim is still used for headspacing the cartridge to the proper depth in the chamber. However, since the diameter of the rim is barely larger than the case, there is less interference with the rim of the next cartridge in the magazine. The rim is wide enough that it is also used by the extractor to pull the cartridge out of the chamber. Examples of semi-rimmed cartridge include the .38 ACP (as illustrated above), the 6.5x50 mm. Arisaka cartridge, the .401 Winchester etc. This type of cartridge is not seen much since the rimless type of cartridge (which we will see below) was developed, but there are still some new cartridges of this type, for instance the .500 S&W Magnum cartridge developed in 2003.

A .500 S&W Magnum cartridge. Click on the image to enlarge.
Image licensed under the Creative Commons Attribution-Share Alike 3.0 Unported by Peter Gnanapragasam

The .500 S&W Magnum rim is used to headspace the cartridge properly in a revolver, but it can also be used in other magazine types because it is a semi-rimmed cartridge.

As manufacturing technologies for cartridges improved, it became possible to manufacture cartridges accurately enough to headspace off the case mouth (for straight cartridge cases) or case shoulder (for bottlenecked cartridge cases). This led to the development of another cartridge type: the rimless type.

Rimless cartridge: Despite the name, rimless cartridges do have a rim. However, in this type of cartridge, the diameter of the rim is almost the same as that of the cartridge case body. There is only one purpose of the rim: it is used by the extractor to pull the cartridge out of the chamber. There is a groove between the rim and the case body, into which the lip of the extractor can engage to pull the cartridge out,

Since the diameter of the rim is the same as that of the case, obviously we cannot use the rim for headspacing the cartridge in the chamber. So how does it work for these cartridges? The following images show us how this is done:

In the case of straight cartridge cases, the case mouth is not crimped onto the bullet, as is done with revolver cartridges. This leaves a little projection in the case mouth that can be used to headspace the cartridge in the chamber correctly:

Click on the image to enlarge. Public domain image.

The above image shows a .45 ACP cartridge loaded into the chamber. Since the cartridge rim is the same diameter as the case body, this cartridge is headspaced against the throat of the cartridge.

Another way to do it is to shape the cartridge into a bottle-neck shape. For this type, the headspacing happens against the shoulder of the cartridge.

Click on the image to enlarge. Public domain image.

As you can see in the image above, the contact point at the shoulder of the cartridge ensures that the cartridge fits into the chamber at the proper depth.

As manufacturing technologies of cartridges improved in the late 1890s, it became possible to mass produce rimless cartridges that would headspace correctly. The rimless cartridge type quickly became the most popular type of cartridge and has remained so to the current day. Since it has no protrusions to complicate the feeding process, the rimless cartridge type has become well suited for most higher capacity modern magazine types, e.g. box magazines, drum magazines, ammunition belts etc. The easier feeding process also made it possible to produce modern rapid-firing weapons, such as machine guns, sub machine guns etc. Some early rimless cartridges include the 9x19 mm. Parabellum pistol cartridge (Luger cartridge), the .30-03 cartridge from 1903, followed by the .30-06 from 1906, the .45 ACP designed by John Browning in 1904 etc. All these cartridges are still widely used currently, along with more modern designs, such as the 7.62x51 mm. NATO / .308 Winchester and 5.56x45 mm. NATO / .223 Remington cartridges.

In our next post, we will study a couple more types of cartridge rims.


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Sunday, October 25, 2015

Cartridges Rims: Rimmed vs. Semi-Rimmed vs. Rimless vs. Belted vs. Rebated - Part I

In the next few posts, we will study different types of cartridges by a specific part of the cartridge: the rim. We will discuss five different types of cartridge rim types: Rimmed, Semi-Rimmed, Rimless, Belted and Rebated rims. We will study the features and differences and the reasons that these were manufactured throughout history.

So, first let's start with the definition of a rim. If you look at the back part of any metallic cartridge case (the end opposite the bullet), you will see a sort of a flange at the base of the cartridge. This flange is called a "rim" and has existed ever since the first metallic cartridge was invented. It serves multiple purposes:

  • During manufacturing the cartridge, it helps hold the case in position while the propellant and bullet are being loaded into the case.
  • It provides a place for the firearm's extractor to latch on to, to pull out a fired cartridge case out of the chamber.
  • In some cartridge types, it helps to headspace the cartridge (i.e.) place it into position in the chamber at the correct depth.
  • In a particular type of cartridge called rimfire cartridge, the rim contains the priming compound that serves to ignite the propellant of the cartridge, when struck on the rim.
Rims can be added to a cartridge case by various methods: stamping, pressing, casting, molding etc.

With that said, let us look at various rim types. The first one we will study today is the Rimmed cartridge.

This is the oldest type of cartridge and dates back to the time when metallic cartridges were first invented. These cartridges have a rim that is quite a bit larger in diameter than the base diameter of the cartridge. The image below shows a rimmed cartridge.

A rimmed .22 LR cartridge. Click on the image to enlarge. Public domain image

Back in the old days when metallic cartridges were invented, mass manufacturing technologies were not so precise and cartridges of the same caliber would have varying lengths. Therefore, there needed to be some way to hold the cartridge to the proper depth in the chamber so that the firing pin could impact it. Providing a rim larger than the diameter of the cartridge case proved to be a simple solution to this problem, since it could be manufactured cheaply.

Click on the image to enlarge. Public domain image.

As you can see in the above figure, the rim of the cartridge is what prevents it from sliding all the way down through the barrel, since it is significantly larger than the hole in the barrel. Therefore, the rim provides positive headspacing. Since the cartridge headspaces on the rim, the overall length of the cartridge is not critical. Back when cartridge manufacturing technologies were fairly basic, you can see how rims solved the problem of seating the cartridges in the chamber correctly.

The rim also provides a secondary function. Firearms such as shotguns and revolvers need to have some way to easily extract the cartridge cases. The rims provide the means for the extractor to hook on to them and pull out the cartridges from the cylinder (for a revolver) or chamber (for a shotgun):






Most revolvers and shotguns still use rimmed cartridges to this day.

For the .22 LR cartridge (which is the most popular cartridge in the world), the rim also serves a third function. The .22 LR belongs to a family of cartridges called the rimfire cartridges. The patent for rimfire cartridges date back to 1831. The idea is that the priming compound is placed on the entire rim and the rim is designed of thin material. When the rim is struck, it ignites the primer, which burns along the entire rim and ignites the main propellant. Back when black powder was not so high-quality, this provided a reliable source of ignition. The .22 LR is only one of a family of rimfire cartridges, but it is the most popular cartridge in the world and has been in production since 1887.

One more interesting thing about rimmed cartridges is that since they headspace on the rim, it is possible for a firearm that is designed to fire longer cartridges to safely fire shorter cartridges if they have the same sized rim. For instance: 

From left to right: .22 CB, .22 Short and .22 Long Rifle (.22 LR) cartridges
Public domain image.

The above three cartridges are of different lengths, but the cartridge case diameters and the bullet diameters are the same and they all have the same sized rims. This means that a firearm that is designed to fire the longest one of the three (the .22 LR) can also fire the lesser powered cartridges, the .22 CB  and .22 Short. This is because the three cartridges all headspace to the same depth in the chamber because their rims are all the same size.

Similarly, .38 Special cartridges may be fired from a revolver designed for .357 Magnum because the two cases share the same rim diameter (and the .357 revolver is designed to fire higher pressures than what the .38 Special cartridge produces).

A word of warning: While different sized cartridges may fit into chambers designed for other cartridges, it is not always a good idea to try this out. For instance, .38 Long Colt, .38 Special and .357 Magnum cartridges all headspace the same, but firing a .38 Special or a .357 Magnum out of a revolver designed for .38 Long Colt is a bad idea, since the revolver is not built to the pressure that these cartridges can produce.

In the metric system of naming cartridges, a capital "R" added to the end of the cartridge designation indicates that this is a rimmed cartridge. For example, 7.62x54mmR is a cartridge that has a 7.62 mm. diameter bullet and the "R" at the end indicates that this is a rimmed cartridge case. The same is true with the 5.6x35mmR (known in the US as .22 Hornet), 7.7x56mmR (a.k.a .303 British), 9x33mmR (a.k.a. the .357 Magnum) etc.

Rimmed cartridges work very well with revolvers and shotguns, as well as some early repeating rifles that loaded from tubular magazines. Unfortunately, they don't work so well with firearms using box magazines, because the rims tend to interfere with each other during the reload cycle. Since the rims don't ride easily over each other, the rim of the cartridge being chambered often tries to strip the round beneath it in the box magazine. However, certain rifles (notably the British .303 Lee Enfield and the Soviet Mosin-Nagant) solve this problem by carefully arranging the cartridges when the magazine is initially loaded, so that the rim of each case is loaded ahead of the round beneath it. If this arrangement of the cartridges is not done properly, there will be misfeeds and jams with box magazines. We will study how this was solved in the next post, when we study about semi-rimmed and rimless cartridges. 

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Thursday, November 18, 2010

What is the difference between a rifle, SLR, submachine gun, carbine etc.?

A very common question among newbies to firearms history is "What is the difference between a rifle, a sub machine gun, a machine gun, a carbine, SLR, assault rifle etc." This post attempts to point out the differences and name famous weapons of each type.

Rifle: The name "rifle" originally comes from the fact that the barrel of such weapons is "rifled". This means that the barrel has grooves in it to impart spin to the bullet as it comes out of the barrel. This spin helps to stabilize the bullet as it travels through the air and gives it a predictable drift (e.g.) a particular rifle may fire bullets that travel 1-2 cm. to the right every 100 meters on a windless day. This feature allows the user to reasonably predict where a bullet will hit and gives the rifle its accuracy. Earlier firearms, such as muskets, had smooth barrels. Smooth bore weapons were much easier to manufacture than rifles, but lacked in accuracy, as the bullets didn't have stability in the air and deviated in a random direction from the intended target. Therefore, the standard strategy for European armies of that period was to line up men in parallel lines and tell them to all simultaneously open fire at the enemy, because almost no one could reliably hit the enemy that he was actually aiming for. This massed fire strategy worked because some enemy would be hit, even if they weren't the ones that were originally targeted. These days, most modern firearms, even small ones, such as revolvers and pistols, have rifled barrels. Therefore, in modern times, the word "rifle" by itself, implies a firearm that has a rifled barrel, is designed to be fired from the shoulder, is manually fed (i.e. after each shot fired, the user has to manually operate a lever to feed a new cartridge into the weapon) and carries a small number of cartridges internally (say 1 to 5 cartridges). Examples of modern rifles from the early 20th century would be the famous American .30-06 M1903 rifle, the British 0.303 Lee-Enfield, the Mauser M98 etc.

Assault Rifle: In the early part of the 20th century, it was realized by some military forces that most conscripted troops, who were hastily trained in wartime conditions, had less than a 50% chance of hitting a target beyond 300 meters. It was also realized that most infantry encounters occurred at less than 500 meters and rate of firepower was also an important factor in these encounters. It was therefore reasoned that there was no need to give such soldiers a weapon and ammunition capable of hitting targets at 2000+ meter ranges, since most soldiers could not hope to hit a target that far away in the first place. Instead, it was reasoned that it was better to give troops lesser powered (and therefore, smaller and lighter) ammunition to suit the actual ranges that most infantry engagements occurred at and a correspondingly lighter weapon suited to fire this ammunition. With lighter ammunition and weapon, the soldier could carry more ammunition and therefore use a weapon with a higher rate of fire. While the concept was around before World War II, it was the German StG 44 (Sturmgewehr 44) that really popularized the concept. The word Sturmgewehr was coined by Adolf Hitler and literally translates to "Storm Rifle" (the word "storm" being used in the context of "storming a castle" or "assaulting a castle") and the term "assault rifle" is actually a translation of "Sturmgewehr". Even though there were earlier weapons that could be classified as assault rifles, many historians consider the StG 44 as the first to form the concept of modern assault rifles. In these times, an assault rifle is a weapon with the following characteristics:
  • Has a rifled barrel (as in the case of the rifle described in the previous section).
  • Has provision to be fired from the shoulder, just like a rifle.
  • Uses an intermediate powered cartridge. This means that the cartridges are smaller than those used by a regular rifle, but larger than the cartridges used by a pistol. This is one of the key differences between an assault rifle and a regular rifle.
  • Is capable of selective fire modes. This means it allows the user to select between firing different numbers of shots each time the trigger is pulled. In semi automatic mode, the weapon will shoot one bullet each time the trigger is pulled. The weapon automatically chambers the next cartridge to fire, but the user needs to let go of the trigger and pull it again to shoot it. In burst mode, the weapon will fire a preset number of cartridges (say 2 or 3) with each trigger pull. In fully automatic mode, the weapon will continue to keep firing as long as the trigger is pulled and there is ammunition. The ability to switch between various modes of fire is a key feature that distinguishes an assault rifle from other types.
  • Has a detachable magazine. Most modern assault rifle magazines carry 20 to 30 cartridges or so.
Examples of assault rifles include the AK-47 family, the M16 family etc.

SLR: This is an acronym for "Self Loading Rifle". The term "SLR" is usually used in commonwealth countries. This has some common features with the assault rifle described above. Like the assault rifle, this is also a weapon that has a rifled barrel and is designed to be fired from the shoulder. It also uses an intermediate powered cartridge and has a detachable magazine like the assault rifle concept. The one key difference between assault rifles and SLRs is that SLRs have only one firing mode, the "semi-automatic mode". This means that each time the user pulls the trigger, the weapon will fire only one cartridge. It will automatically eject the fired cartridge, load the next cartridge and prepare the weapon to fire, but the user has to let go of the trigger and then pull it again to fire the next cartridge. This is unlike an assault rifle, which has multiple firing modes and allows the user to switch between them. Examples of SLRs would be weapons like the American AR-15 and the Indian Ishapore 1A1 SLR. The AR-15 is a semi-automatic version of the M16 rifle and the 1A1 is a semi-automatic version of the Belgian FN FAL assault rifle.

Carbine: This is a term used for weapons that are versions of rifles or assault rifles, but with a shorter barrel and lighter weight. Carbines are bigger than pistols, but smaller versions of rifles. In the days of the Wild West, mounted riders preferred a shorter and lighter firearm because these were easier to operate than full sized firearms, when riding. In more modern times, people inside moving vehicles or in close quarter jungle combat, preferred shorter weapons for the same reason. Since carbines have shorter barrels, they lack in accuracy compared to full sized rifles or assault rifles. While they use the same cartridge as their full sized cousins, the shorter barrel also means reduced velocity bullets. Many assault rifles also come in a carbine version. For example, the American M4 (a carbine version of the M16 assault rifle), the Israeli Galil SAR (a carbine version of the Galil assault rifle), Steyr AUG carbine ( based on Steyr AUG assault rifle. The carbine form uses a 16 inch barrel, whereas the assault rifle uses a 20 inch barrel) etc.

Submachine Gun: This is a weapon that shares some similarities with assault rifles, but one key difference is that submachine guns are designed to fire pistol cartridges instead of intermediate cartridges. As a result of this, submachine guns are generally lighter and smaller than assault rifles and are about the same dimensions or smaller than carbines. Since they use pistol ammunition, they also have less recoil and therefore can be fired from either the shoulder, the hip, or even holding it like a pistol. The first weapon to use the term "submachine gun" was the famous Tommy Gun that we studied about earlier. This is a fully automatic weapon that fires .45 ACP cartridges, the same cartridge used by the Colt M1911 pistol. Another famous submachine gun from the World War II era is the British Sten gun, which is also a fully automatic weapon. Modern submachine guns such as the Heckler and Koch MP-5 are capable of selecting multiple firing modes. Submachine guns are more preferred for close-range combat in urban environments because, with lower powered pistol cartridges, there is less risk of bullets penetrating through walls and hitting innocents on the other side

Machine Gun: This generally denotes a weapon that is capable of rapid, fully automatic fire and carries a large supply of ammunition. Fully automatic fire means that the weapon will keep firing as long as the trigger is pulled and there is a supply of ammunition available to it. Most machine guns fire either full sized or intermediate sized ammunition, similar to rifles and assault rifles. Machine guns generally carry a large supply of ammunition in ammunition belts, drum magazines or box magazines. This means that they generally have hundreds of cartridges available to them, unlike the 20-30 cartridge magazines used by assault rifles. They are also generally heavier than rifles and assault rifles. Examples of machine guns would be the Gatling Gun, the Gardner Gun, the Bira gun etc. Modern machine guns include the Browning Automatic Rifle (BAR), the British Bren gun, the American Stoner 63, the Belgian FN Minimi etc.
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Tuesday, July 6, 2010

Actions: Bolt Action

In the last couple of posts, we studied the break-open action and the sliding barrel action. Now we will study another type of action that is known for its sturdiness and is still with us. This action is the bolt action.

We actually studied the first weapon to use a bolt action a while earlier. It happens to be the Dreyse Needle Gun. This gun had a number of firsts to its name:
  1. It was the first mass-produced military weapon using breech-loading technology.
  2. The ammunition it used burned almost completely, so it didn't need to eject the paper casing after firing the weapon. This was a precursor to caseless ammunition.
  3. It was the first bolt-action breechloading weapon.
The action was a significantly new invention in 1841, when the Dreyse needle gun was first introduced. It allowed the user to reload significantly faster than the opposition who were still using muzzle-loading weapons (almost 5 times the shooting speed). It also had the advantage that the user didn't need to stand up to reload the weapon and therefore could hide behind cover.


The basic idea of a bolt-action weapon is a manually operated bolt, which is manipulated by a handle, typically on the right side of the weapon. The handle is used to unlock the bolt and open the breech cover. The old cartridge case is then ejected from the breech chamber. The opening of the bolt may also cock the weapon in some models. Then a new cartridge is put in the chamber and the handle is then moved forward to close the bolt. In some models, the action of closing the bolt cocks the weapon. The weapon is then ready to fire.

In some models, opening the bolt causes an extractor lever to automatically pull the old cartridge case out of the chamber to eject it. The magazine has a spring that pushes a new cartridge into the chamber, when the old cartridge case is pulled out by the extraction lever. Such a mechanism is used in many bolt-action rifles, such as the Springfield M1903 rifle which carries a 5-shot magazine under it. This speeds up shooting because the user doesn't need to waste time pulling out the old cartridge or feeding a new one by hand.

Compared to other actions, the bolt-action has a few advantages. It is extremely simple to make, yet has very high accuracy. It is very cheap to manufacture and very light-weight. Best of all, it is a very strong action and can handle powerful cartridges. The only downside to it is that it doesn't support a very high rate of fire compared to some other alternatives. Since most modern military rifles are semi-automatic or selective fire weapons, they don't use this mechanism. However, the simplicity combined with the accuracy and the ability to handle high powered cartridges make it ideal to be used in sniper rifles. In fact, the bolt-action is overwhelmingly the action of choice in most of the sniper rifles used throughout the world. This mechanism is also used in many hunting rifles, where rate of fire is not as important as accuracy and power.

There are three major variants of bolt-action rifles which we will study below.

The Mauser M-98 system was first introduced in 1898 (hence M-98) with the Mauser Gewehr 98 rifle, which was used by the Germans between 1898 and 1935. This highly successful bolt-action design was later used in a lot of other rifles and is the dominant form of bolt-actions used today. In this type, the rifle is cocked when the bolt-action is opened. The Gewehr 98 has a 5-round magazine.


Click image to enlarge

The image above shows an original Mauser model from 1898. The weapon was designed with a lot of thought. The bolt handle is securely attached to the bolt and there are a couple of gas vent holes built into the bolt, so that if there is a rupture in the cartridge case or primer, the hot gases will vent out of the magazine hole instead of near the user's face. The "controlled feed" extractor claw holds on to the cartridge the moment it has fed from the magazine and holds on to it until the cartridge case is ejected. The weapon is cocked as the bolt is opened (actually, it specifically cocks as the bolt handle is rotated upwards, before pulling back to open the bolt) and the rear part of the striker protrudes from the back of the bolt, which allows one to quickly check if the rifle is cocked or not visually. The original mauser design was not given to cheap mass-production.



The cock-on-bolt-opening design was later adopted by other rifles as well, notably the Springfield M1903 (like the one shown in the picture above). The M1903 was used in the US military from 1903 all the way into the Vietnam war. The cock-on-bolt-opening design rifles are slightly slower to load than the other variant which we will study below. However, it is the more common of the two variants of bolt action and is used in nearly all modern hunting rifles today. It was also the dominant form of action used between the 1890s and the mid 1900s.

Another variant of bolt action is the cock-on-bolt-closing design. This is famously called the "Lee Enfield design" as it was first used in the Lee-Enfield rifle of 1895, otherwise known as the SMLE (Short Magazine Lee-Enfield) rifle. This rifle was heavily used in the British Commonwealth and its descendant is still used by Indian police, which makes it the longest serving bolt-action rifle model in existence.


The above is an example of a Lee-Enfield Mark I rifle. In this rifle, pushing the bolt closed cocks the rifle. This makes opening the bolt a lot faster and smoother, compared to the cock-on-opening design of the Mauser. This feature, coupled with its larger capacity 10-round magazine meant that a user could shoot 20-30 times in 60 seconds, making it the fastest bolt-action rifle of its day. The Lee Enfield rifles fire a 0.303 bullet. Note that the 0.303 bullet actually measures 0.311 inches in diameter, as we have noted previously.

The Indian Ordnance board later made a variant of this rifle called the Ishapore 2A1, which was based on the Lee Enfield Mark III rifle model.


The main difference is that the Ishapore 2A1 rifle is chambered to fire a standard NATO 7.62 x 51 mm. round. As a result of this, the steel used in this weapon is also improved to handle the higher pressures of the NATO cartridge. This rifle has the distinction of being the last bolt-action rifle designed to be used by a regular military force (other than sniper rifles, which are for special forces only). It is still used by police in various states in India. It is also popular with civilian shooters in the UK and USA.

The Lee-Enfield cock-on-closing-bolt system was also used on a number of other rifles, mostly made in the UK and other commonwealth countries.

A third variant is the Mosin-Nagant system, which was first used by the Mosin-Nagant rifle in 1895. Unlike the Mauser system, the bolt head rotates with the bolt and lugs, whereas the Mauser has the bolt head is an integral (non-removable) part of the bolt. It is also unlike the Lee-Enfield where the bolt head remains stationary and the bolt alone rotates. It is a rugged design, but is complicated. This type of bolt-action was mostly used in Russia, but one version called the M28 was manufactured by the Finns. The M28 is widely regarded as one of the finest and most accurate military rifles ever produced and was used by the most successful sniper of all time, a Finn named Simo Hayha.

There are other bolt-action systems, but never caught on as much as the above three systems.

Bolt actions are more accurate than semi-automatic rifles, which is why hunters and military snipers still use them. The reason is because when the cartridge is fired, the entire energy is devoted to propelling the bullet out of the rifle, unlike a semi-automatic or automatic weapon, where part of the energy is diverted to eject the old cartridge, auto-cock the weapon and load a new cartridge. It also has less moving parts than most other action types. The only parts that really move in a bolt-action when it is being fired are the spring and the firing pin. This simple and strong design means it can fire magnum cartridges as well. One more advantage for snipers is that it does not eject the spent round automatically, which is beneficial to the sniper because it does not give away his position and he can decide to eject the round himself when it is safe to do so. The only disadvantage is that it is slower to use than some other actions. So, while it may not be as useful to an ordinary infantryman, this action is more valuable to snipers and hunters and has thrived for these reasons even to the present day.


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