Wednesday, May 28, 2014

Tubular Magazines

In our last post, we studied the basics of magazines and also the difference between a magazine and a clip. In today's post, we will study a particular type of magazine, the tubular magazine.

Tubular magazines were among the very first types of magazines to be used in repeating weapons. It consists of a tube that can hold cartridges placed end-to-end. In many cases, there is a spring on one end of the tube, that serves to push the cartridges into the chamber. The tubular magazine is usually placed under the barrel, or in the butt-stock of the firearm. These are usually used with lever-action rifles or pump-action shotguns. Tubular magazines are also usually of the "fixed" type (i.e.) they cannot be detached from the firearm in normal usage.

A Winchester model 1873 lever-action rifle. Public domain image.

In the above image, we see a Winchester Model 1873 lever action rifle. Note the cartridges are shown stored in a magazine tube under the barrel of the firearm. There is a spring on the other end of the magazine tube, that forces the cartridges backwards out of the magazine. When the user manipulates the trigger guard lever, it pulls a cartridge out of the magazine and chambers it.

In the above image, we see a pump-action shotgun. You can clearly see the extra shells being stored in a tubular magazine under the barrel.

Not all tubular magazines are necessarily under the barrel though. Let us look at a very early repeating weapon, the Spencer carbine (and its larger cousin, the Spencer repeating rifle).

A Spencer Carbine. Public domain image.

The Spencer rifle and carbine were invented in 1860 and preceded the Winchester model 1873 that we just studied above. Unlike the previous examples where the magazine is under the barrel, this weapon stores its cartridges in a magazine in the stock and there is a spring mechanism at the butt end of the stock that pushes the cartridges out of the magazine and into the chamber.

Not all tubular magazines were necessarily spring fed though. In very early repeating rifles such as the Kalthoff repeater and the Girardoni air rifle, both of which we studied a couple of months ago, gravity is used to feed a new bullet from the magazine. The user typically tilts the rifle upwards and manipulates a lever to load a firearm. Due to gravity, a bullet rolls down from the magazine and into the chamber. Of course, this mechanism was used before the invention of cartridges and also when bullets were round balls.

In some of the above images we've seen above, note that the cartridges have pointed bullets (a.k.a. spitzer bullets). If the cartridges are of the centerfire type, this means the pointed end of each bullet is resting against the primer cap of the cartridge ahead of it. In early repeating rifles, these sometimes caused problems because the pointed nose of one bullet could sometimes detonate the cartridge ahead of it, if enough force was applied. This could happen if the user were to accidentally drop the weapon, or even due to recoil after firing a cartridge. Sometimes, this could also result in a chain fire, where every bullet detonates the cartridge ahead of it. The risk of premature detonation increased as rifles got more and more powerful because of the increased recoil forces. Therefore, tubular magazine are generally seen these days on weapons that don't use pointed spitzer type bullets, but use other types of bullet shapes, such as shotgun shells (which have flat tips), round-nose bullets or rimfire cartridges (because the primer is in the rim, rather than in the center of the cartridge base). This is why they are usually seen today in shotguns and rimfire rifles mostly. They also don't generally have the capacity compared to some other magazine types (typically, they hold 3 to 12 cartridges). Another issue is that it is usually not possible for the user to see how many cartridges are left in the magazine. On the plus side, it is a very simple magazine mechanism and has been used for several decades.

Monday, May 19, 2014

Magazines and Clips

It has been four years since this blog was first started and guess what? We haven't talked about magazines yet. In the next series of posts, we will discuss different types of magazines that are used in firearms.

With that said, let us discuss a couple of terms which many people get confused about: what is the difference between a clip and a magazine? Many people believe that they are the same thing and use the words interchangeably. However, they are incorrect and there are some major differences between the two.

A magazine is a device that is used to hold cartridges for feeding into a firearm's chamber, during the operation of the firearm. It may be of a fixed type or a detachable type and comes in a variety of shapes (box, tube, drum etc.).

A clip, on the other hand, is used to conveniently hold a bunch of cartridges, before inserting them into a magazine. They are generally used for quicker reloading of magazines. Depending on the type of clip, it may or may not remain inside the magazine during operation of the firearm.

A magazine also has some kind of feeding mechanism (usually powered by a spring), which is not present in a clip. A clip may sometimes have a spring too, but a clip's spring is not part of a feeding mechanism, it is just there to hold the cartridges in the clip.

For some reason, many people incorrectly refer to a detachable magazine as a clip, even though they are very different devices.

In this post, we will only look at a few types of clips and then study magazines in more details in the following posts. Remember, they are different devices!

Moon clip

A moon clip, such as the one shown in the image above, is usually used to quickly reload a revolver.

Another type of clip is the stripper clip (also known as the charger clip in commonwealth countries). These were originally invented by Mauser in 1888 and used by some rifle models. It consists of a long strip of metal into which cartridges may be slid into. With a stripper clip, the user opens the bolt and places the clip on a special slot behind the magazine and then slides the cartridges off the clip and into the magazine ('stripping' them off the clip into the magazine, this is why it is called a "stripper clip"). After the magazine is reloaded, the stripper clip is removed and saved for re-use.

There is also another type called the en bloc clip, that was used by Mannlicher in 1885 and by some other rifles since. In this type of clip, the cartridges and the clip are inserted together into the fixed magazine of a rifle. When the last cartridge is chambered or fired, the clip is ejected out.

Left: An en-bloc clip. Right: A stripper clip. Click on image to enlarge.
Public domain image

With that said about clips, we will study different types of magazines in the next few posts. Remember, clips and magazines are different devices!

Sunday, May 18, 2014

Ancient Techniques of Rifling Machines - IX

In our last post in this series, we studied a completely assembled rifling machine, as used by ancient gunsmiths. Until now, what we were studying were a bunch of descriptions and some hand-drawn pictures (hopefully not too badly drawn :)). It is now time for show and tell. In today's post, we will look at some actual images and movies of people using machines to cut rifling by hand.

Some of the following images are taken from a book published in 1941, called Rifle Making in the Great Smoky Mountains, authored by Arthur I. Kendall for the US National Park Service. This book is now in the public domain.

First up, we have a picture of a person using a spring pole lathe to make a wooden cylinder, as the first part of constructing an indexing guide:

Click on the image to enlarge. Public domain image.

Notice how the woman is powering the lathe with her foot, while using her hands to shape the log into a cylinder. For those who like to see one in action, here's a short movie demonstrating a spring pole lathe being used by a person:

After the log is shaped into an uniform cylinder, the next step to making an indexing guide is to mark the spirals on the outside of the log surface.

Marking the indexing guide. Click on the image to enlarge. Public domain image.

In the above image, the woman has wrapped a thin ribbon around the cylinder's outer surface and is marking the edges of the ribbon with a pencil. She will then use a chisel to carve out the wood between the pencil marks.

Cutting the indexing guide. Click on the image to enlarge. Public domain image.

In the above image, the woman is carving out the indexing guide using a sharp chisel. Typically, the depth of each groove is about 1/2 inch. Notice that she's cutting multiple grooves on this guide. The description we studied earlier only relied on a single groove, but multiple grooves can be used for more accuracy.

Part of the rifling machine with indexing head, head piece and tail piece assembled. Click on image to enlarge. Public domain image.

The above image shows a partially assembled rifling machine. The indexing head, head piece and tail piece have been assembled and attached, similar to what we had studied earlier here.

A complete manual rifling machine. Click on the images to enlarge. Public domain images.

In the above two images, we see the rifling machine completely assembled, similar to the one we had studied earlier here.

After seeing all the pictures, let us now watch some movies showing this machine in action.

In the above movie, the gentleman describes how he made his indexing guide, using a process very similar to what we studied earlier. Also notice that unlike the pictures above, his indexing guide only has one groove on it. The gentleman also goes on to describe the process of cutting the grooves in some detail.

In the above movie, we see a gunsmith from the Hensley settlement in Ewing, VA, showing us how his rifling machine works. It is a short movie, but it shows the basics of operation of the machine.

Finally, we have another longer movie, where the person shows how he cut rifling using a rifling machine that he made from scratch by himself. While some of tools he used are a little more modern, it is interesting to note that most of the basic principles are unchanged. Interestingly, he marks his indexing guide free hand, instead of using a thread as we studied previously and his indexing head is merely a screw. His design is also a lot more compact and cuts handgun barrels.

Happy viewing.

Tuesday, May 13, 2014

Ancient Techniques of Rifling Machines - VIII

In the last seven posts of this series, we've looked at various parts of a cut-rifling machine, as was typically used by gunsmiths from the 16th century to a good part of the 20th century. As we have noted repeatedly in this series, the tools and techniques used to make the various parts of the machine were well known and fairly commonly available to people. The skills to make the various parts of the ancient cut-rifling machine were also known to carpenters, wheel-wrights, clock-makers and blacksmiths. In the early days of gun-making, blacksmith guilds worked in collaboration with carpenter and clock-making guilds to make firearms, before the advent of separate gunsmith guilds, which combined the skills of the other trades into their own specialized guilds.

In today's post, we will study how all the parts that were described in the previous seven posts, would have been combined together by an ancient gunsmith, to make a serviceable cut-rifling machine. The following diagram shows the assembled machine:

Click on image to enlarge. Image is not to scale. 
Author places the image in the public domain.

A few points to note: In the absence of modern lubricants, the ancient gunsmiths were known to use tallow or lard as lubricants instead. We already saw how tallow was made in an earlier post. Lard was made in a similar process (the main differences being, lard is made of pig fat, whereas tallow is made of beef or mutton fat and different parts of the pigs, cattle or sheep are used for lard or tallow as well). The rifling cutter tool would have been liberally coated with tallow or lard, to reduce friction and to cut more efficiently. Lard and tallow were also historically used in many cooking recipes (as a bit of trivia, McDonalds used to cook their fries in tallow until about 1990), so they would have been easily available to ancient gunsmiths.

In the above image, only two barrel clamps and two support blocks are shown. The actual numbers and positions of these could vary depending on the length of the barrel being machined. Also, the indexing guide is shown with only a single groove. In many cases, gunsmiths would cut multiple grooves on the indexing guide, so that errors in one groove would be largely cancelled out by the other grooves on the indexing guide.

As the head piece is pushed forwards and backwards, it causes the indexing guide to rotate at a fixed rate. This motion is transferred to the rifling cutter (which is inside the barrel) via the extension rod, to cut a rifling groove.

The ancient gunsmith would have first taken the barrel and made markings on the outside, corresponding to the number of grooves required for the barrel (or attached a larger indexing guide disc to the end of the barrel, with a number of markings/holes in it, corresponding to the number of grooves required in the barrel. By the way, if any of my faithful readers would like to know how to divide a circle evenly into 5 or 6 parts using only a straight edge and a set of compasses, please post a comment and I'll make a separate post for that). The gunsmith would have then mounted the barrel so that one of the markings aligns with a fixed marking on one of the barrel clamps or on a support block. The barrel clamps would have been tightened and then the gunsmith would have pushed and pulled on the head piece, until the cutting tool stops cutting. Then the gunsmith would have unclamped the barrel and rotated it to the next marking and repeated the process of pushing/pulling to cut the next groove and so on, until the required number of grooves were cut. Then, the gunsmith would have adjusted the cutting tool to increase the depth of cut (as described here) and repeated the process again, until the required groove depth was reached for all the grooves.

Person demonstrating a traditional rifling machine, as built in the Great Smoky Mountains region.
Click on image to enlarge. Public domain image.

The above picture shows a traditional rifling machine, as built by American backwoodsmen in the Great Smoky Mountains area between North Carolina and Tennessee. 

In the next post, we will study some pictures of the build process, as well as a couple of videos showing an ancient rifling machine in action. Until then, happy reading.

Monday, May 12, 2014

Ancient Techniques of Rifling Machines - VII

In our last post, we saw how ancient gunsmiths would have manufactured barrel clamps and the extension rod. In today's post, we will study the last few bits of ancient rifling machines and then study how they would have all been put together.

The first part is the supporting block. This is simply a block of wood that is used to support a barrel while the rifling is being cut. The simplest way to support a cylinder is to cut a v-shaped groove in a block of wood and the cylinder will be supported by the sides of the groove.

Click on image to enlarge. Public domain image.

Typically, ancient gunsmiths chose wood blocks made of pine or maple and simply carved out a v groove on top of each block, using a wood chisel and a mallet. The length of the V is made big enough to support a barrel through the groove. The gunsmith would have used two or more of these support blocks to support a barrel. In order to ensure that the support blocks don't move, the gunsmith would have either nailed the blocks or glued them into the proper positions on the machine. Another common technique used was to drill a couple of holes into the base of each support block and into the bed of the machine and use cylindrical wooden pegs to hold the support blocks in place.

The gunsmith could optionally also use C shaped strips of metal and screws to clamp the barrel to the support block. These could be used by themselves, or in conjunction with the barrel clamps we studied in the previous post.

The next part we will study is the bed of the machine. This is simply a long plank of wood, with holes drilled in specific places, so that the various other parts (such as the support blocks and barrel clamps) can be attached to it. As we saw in an earlier, mankind had already invented drills and reamers centuries ago, so these tools were easily available to gunsmiths in the 16th century. And as for ensuring that the surface of the bed is flat, the tools to do this were also invented by carpenters a long time ago. Ancient carpenters used a tool called an "adze" to make wood planks. Adzes have been known to exist since the Stone Age and were used by many cultures around the world (Egyptians, Mayans, Europeans, Indians, Chinese, Maoris, Polynesians, Hawaiians, Native Alaskans, Zulus etc.). Some time during the Roman era, the plane tool was invented to replace the adze and rapidly spread to several countries around the world. Examples of plane tools have been found in the ruins of Pompeii. Therefore, we can safely assume that gunsmiths in 1550 AD would have had access to good woodworking planing tools.

A Roman woodworking plane tool. Click on image to enlarge.

A modern planing tool made by Stanley Tools. Click on image to enlarge.

In the above images, we see two plane tools. The first one dates from the time that the Romans ruled England and the second one is a more modern version made by Stanley Tools. It is interesting to note the similarities between the two hand tools, considering that they are separated by almost two thousand years. The manual plane tool is only seen in small home workshops these days, as it has largely been replaced by the electric planers for quicker production.

Finally, our ancient gunsmith would have constructed a set of table legs to attach to the underside of the bed. Again, this is something that practically every village carpenter in Europe or Asia already knew how to build for thousands of years, so gunsmiths weren't inventing anything new.

In the next post, we will see how all these parts were assembled into a rifling machine that ancient gunsmiths used.