lees-gunsmithing

The Safe Capping of the Percussion Revolvers

Tue, 24 May 2022 04:43:18 GMT

Capping the Percussion Revolver

The proper method of attaching percussion caps to the C&B revolver, in preparation for firing, has been the subject of much discussion of late. To help resolve this issue, the Brimstone Pistoleros recently ran a series of tests, on several different models of C&B revolvers.

The revolvers chosen to evaluate were the Colt M 1860, Remington M 1858, Rodgers & Spencer M 1865, and the Ruger Old Army. Examination of these four revolvers brought to light that the Rodgers & Spencer and the Ruger Old Army are designed in such a way that if a chamber were to discharge at the capping position (90° to the right of the barrel), the ball, leaving the chamber would have no contact with any part of the arm. The Colt and Remington designs, on the other hand, do have points of interference between a ball launched from a chamber in the capping position and the frame or other part of the arm. Figures 1 and 2 show the Rodgers & Spencer and the Ruger clearance.

Figure 1

Figure 2

When the percussion caps are placed on the nipples of a C&B revolver, it is the habit of most shooters to apply some amount of pressure to the cap to “seat it” on the nipple. This practice helps to eliminate misfires. If the combination of nipple and cap is correct then only a very slight pressure is required to seat a cap reliably. On today’s shooting ranges you will see three different approaches to the cap seating matter. Some shooters will apply thumb or finger pressure to seat the cap. Another group will install the caps on the nipples and then rotate the cylinder while using the hammer of the firearm to press on the caps. The last group are those shooters that install the caps on the nipples and then use a “Push Stick” to seat the caps at the capping position (90° to the right of the barrel, at the cutout in the recoil shield). The basic question that we have set out to answer is “which method of seating caps affords the greatest range safety?”

On a recent Saturday, a crew arrived at the range with a truck load of equipment and guns. The first order of business was to set up a test cell. Figure 3 shows the screen being built. A position was established for the firearm, and then a screen of clean cardboard was constructed to show evidence of any material leaving the firearm. The screen is at a radius of about 4 feet from the revolver. The revolver was mounted in a “Ransom Rest” (machine rest) so that the P.O.A. would remain fixed. Figure 4 depicts mounting the Colt in the rest, and figure 5 shows the test cell ready for the first shot.

Figure 3

Figure 5

Figure 4

For the entire test, all chambers were loaded the same. The standard charge was 28 grs. of GOEX fffg powder followed by a Wonder Wad, and a Hornady swaged ball of .454” diameter. All caps used were of Remington make.

The first step in the proceedings was to fire a normal shot from the gun under test. This shot was fired to establish the P.O.A. of the firearm. Upon resetting the machine rest, a second shot was fired from the cylinder, while in the capping position (90° to the right of the barrel). At this point it was possible to examine the screen for shrapnel, particles, or any other matter that might pose a hazard to shooters in the area.

In figure 6, the Colt 1860 is seen being fired , with a normal charge, through the barrel. Note the upward recoil of the revolver in the machine rest, denoting considerable energy in the discharge.

Figure 6

The second phase of testing was to fire a charge from the cylinder, out of battery, in the capping position. Figure 7 documents this experiment. Discharging the cylinder produced virtually no pressure, the powder charge burned beside the firearm in the open air. The cameraman was standing roughly where another shooter might be and was not distressed by the little poof of smoke and sparks. Examining the “screen” failed to indicate the presence of any particles, other than the ball. While the ball struck the frame of the firearm, it did not fragment or produce any form of shrapnel. The ball was deflected slightly to the right of the P.O.A. Figure 8 was taken after both the Remington and the Colt revolvers had both been tested. It can readily be seen in the picture that both “normal” shots struck within about 1” of each other. The shot being measured with the tape is from the Remington. This ball was deflected about 7” by contact with the arm. The other hole, another 4” or so farther to the right is the Colt impact point.

Figure 7

Figure 8

At this point it is obvious that an out of battery discharge, that is having a chamber fire while in the capping position will not expose the adjacent shooters to any great danger.

For those that are wondering how it was done!
(Out of battery discharges were accomplished by fabricating a nipple to accept cannon fuse)

Fuse 1

Fuse 2

Fuse 3

The next question was one of energy. Does the out of battery discharge pose a threat at some distance? To answer this question an additional set of tests were performed. The Colt revolver was fired, 5 shots, loaded normally and fired through the barrel. The chronograph established the normal muzzle velocity to be 852 ft per sec. The barrel was then removed from the Colt, figure 9-11 and the arm was fired from the cylinder only.The velocity of a ball discharged from the cylinder was found to have a velocity of 146 ft per sec.

Figure 9

Figure 10

Figure 11

Figure 12

Using the standard Kinetic Energy equation, we may find the energy of the balls.
Ft/Lbs = wv²/450400
Ft/Lbs at the muzzle = 148(852)²/450400 = 238 Ft/Lbs
Ft/Lbs from cylinder = 148(146)²/450400 = 7 Ft/Lbs

Readers who have studied small arms ballistics to any extent will be aware that the ball from the muzzle of our test gun, with an energy of 238 ft/lbs is a DEADLY projectile. While the ball from the cylinder is to be sure, dangerous, I would not class it as deadly.

I have not yet tried this experiment, but I believe a person with a good right arm could throw a bullet hard enough to approach the energy of the ball fired from the cylinder (as loaded and fired in our experiments).

Keeping our test data in mind, lets now consider the various cap seating methods mentioned above. Viewed with an eye to general safety of all shooters in the proximity of the loading bench at a typical CAS event.

Case one, the seating of caps with thumb or finger pressure (or any other body part). The ignition of a cap while seating it, seems to be a very remote occurrence (I can only find three cases that may be true). In order to press the cap with the thumb, the revolver will generally be held parallel to the loading bench or muzzle somewhat down. A ball launched from the cylinder in this position will pose a minimum threat to other shooters. The thumb or finger used to seat the cap will likely require medical attention. The explosive force of a percussion cap is considerable.

Case two, the use of the hammer to seat caps. This is without doubt, a most dangerous practice. A visit to most any CAS range will present an array of loading tables with bullet holes, and chunks of wood blown away by the accidental discharge of a firearm while loading. The vast majority of these ADs are from handguns, discharged while attempting to index them.

The act of seating caps with the hammer is an accident waiting to happen. The probability of a “slipped hammer” accidental discharge is extremely great. Such an accident will loose a full energy projectile! I can think of no greater hazard to the other shooters in the area (It is also a basic violation of SASS policy to lower the hammer on a loaded chamber).

Case number three, the use of a “push stick” seems to offer the greatest overall range safety. If a chamber discharge did occur , the projectile from the “out of battery” position will have very little energy, and therefore be less likely to do serious harm to another shooter in the area. Further the use of a “push stick” will keep the hand of the shooter loading the firearm, in a much safer location.

After consideration of all the data, the “Brimstone Pistoleros”, a SASS affiliated club, a SASS affiliated club have adopted the standard range rule that caps, installed on a C&B revolver, may only be “seated” with the use of a “push stick”.

Old Scout

(Permission must be obtained to use this article or any part there of from the author- Richard Clark -- aka Old Scout)

The Test Crew

High Grove Owen Muny Old Scout Midway Rowdy Yates Cliff Hanger

Can a static spark set off black powder?

Tue, 24 May 2022 04:43:14 GMT

The question: Can a static spark set off black powder?

The question of whether a static electric spark can set of black powder has been debated for a while, and I recall hearing of some previous experiments showing that it could not. Since I am involved in the design of a BP breechloader which is to be electrically fired, I resolved to put the matter to test in two experiments.

The Test Setup:
First, I placed a piece of white writing paper on top of a grounded block of metal and placed a small pile of Swiss 4F powder on the paper; I find that this powder ignites near instantaneously in my flinter. I then placed a wire from a ceramic torch igniter 1/4" over the top of the powder. The igniter generates a pulse of electricity of about 10,000 volts, which is about the most static charge that can be built up on a person. I used a combination of flash and time exposure to capture the image, where I sparked the igniter about 10 times during the course of the exposure.

As you can see, the powder did not ignite. I repeated this several times, and the results were the same. I also tried various BP substitutes, and they did not ignite either.

For the second experiment, I used an Oudin coil, which is used for testing glass neon fixtures for leaks. It produces pulses in excess of 40,000 volts and will give you quite a burn (and shock) if you let it hit you.

This was impressive! The pile of powder was hit dozens of times, and again, it never ignited. You can see little flashes where the sparks strike; these are caused by vaporization of material from the surface. Although I couldn't get a picture of it, the paper had hundreds of tiny holes punched in it where the sparks burned through.

The next picture shows a similar test set-up, except this time the black powder was ground into dust-like consistency. Again, no ignition, even though the sparks striking the middle of the pile blew powder clear from the areas where they struck.

Unique smokeless powder was also tried, this time with even more sparks - again, no ignition.

For those skeptics who might not believe that the sparks actually got near the powder granules, in this experiment, the photo shows sparks passing around and over the individual granules as the spark travels between two electrodes.

So - Why wouldn't all of the sparks set off the powder?

The answer comes from the fact that black powder, and other carbon-containing propellants, are fair conductors of electricity. When a material conducts well, it takes a lot more current to heat it up. This is why the lamp wire stays cool and the filament in your light bulb gets white hot. The same current passes through both, but because the light filament has a much higher resistance to the passage of electric current, most of the heat ends up there rather than in the wire. In the experiment here, the air has a very high resistance, while the powder conducts fairly well. The passage of the spark heats the air white-hot, but the powder stays cool. A very high-current spark (like lightning!) would, of course, heat everything and cause ignition, but this would take much more current than could be provided from a static-like source.

Why Does a Short-Started Ball Cause a Barrel Bulge?

Tue, 24 May 2022 04:43:12 GMT

The Question: Why Does a Short-Started Ball Cause a Barrel Bulge?

If a barrel is obstructed somewhere past the powder charge, the barrel will bulge or blow out just below the point of the obstruction, To understand why this happens, one must remember that the barrel is filled with gas. A very hot gas from the burning of the powder, but a gas nonetheless, and in any gas, a change in pressure (think of it as a change in direction of the gas) can not exceed the speed of sound in that gas, and this speed depends on the temperature and average molecular weight of the gas.

As shown in the diagram above, in the normal course of shooting, pressure builds up in the barrel and accellerates both the powder gasses and the projectile. The gasses behind the projectile move as an expanding column, where the gas molecules just behind the projectile are moving along in step with it, while gasses in the breech pretty much stay in place. All elements are moving smoothly, and with sufficient powder charge, the projectile and the expanding gasses behind it can easily exceed the local speed of sound. Air trapped in front of a projectile which exceeds the speed of sound can't move out of the way fast enough and is compressed and forms a shock wave. When the projectile exits the barrel, the shock wave causes the characteristic 'crack' of a rifle when the muzzle velocity exceeds about 1100 fps.

Now let's take a look at what happens in an obstructed barrel, for example, when the projectile is seated only half way down. When the powder charge burns, it creates an expanding column of gas just like it normally would, but it expands faster, since there is no projectile to push. However, the leading edge of the pressure wave can't travel faster than sound without building up a shock wave in front of it, so the first thing that comes into contact with the obstruction is this shock wave. Unless the obstruction is extremely light, it will slow or stop the shock wave for a few milliseconds, which is all it takes to do the damage. Since the gasses travelling just behind the shock wave are moving at the local speed of sound, they are unable to quickly reverse direction, and most of the column of hot gas plows into the area behind the obstruction - just like a multi-car accident on a freeway, where the cars simply can't stop fast enough. This rapid build-up of gas equals a rapid build-up of pressure; it is almost the equivalent of setting off the powder charge in a closed container, because the gasses are confined in front by the obstruction which can't move out of the way fast enough and in the rear by the gasses coming up the barrel which can't stop fast enough. When you think of it this way, it is no wonder that even a small charge and a light obstruction can ruin a barrel.

The moral is - Never give those powder gasses a running head start; always keep the projectile seated on the charge.

Measuring Black Powder

Tue, 24 May 2022 04:43:10 GMT

How do you measure Black Powder or it's many substitutes?

Do you use a volumetric measure or do you use a scale?

I've often heard discussions that indicate that smokeless powder is measured in grains weight and Black Powder is measured in grains volume. Now I've done a fair amount of reloading over the years, but I've always been somewhat confused by these comments.

Why the confusion? Well if you think about it, unless you weigh each charge on a scale then all gun powder, smokey and smokeless, is measured by volume. For many re-loaders smokeless is kept track of by weight and Black Powder is kept track of by volume simply because BP requires the filling of a given space so that a slight to heavy compression is exerted against the powder when seating the bullet. The amount of compression used is dependent on the obtained standard deviation and accuracy of the round, but then that's another article.

For the most part, I keep track of BP and the subs by weight, the same as smokeless and keep a list of powder charges by name, granulation and weight.

Example: 44 WCF

Powder

Goex

APP

Clearshot

granulation

FFg

FFFg

charge

34 grains

24 grains

30 grains

bullet

200 rnfp

Its fairly easy to see that these charge weights are not in volume.

I do it this way because it is much easier for me to keep track of a given charge for a given load, just as it is with smokeless powder. In my opinion, volume measurement for Black Powder is a field measurement for front stuffers only and is inferior to tracking a measurement by weight. Getting an exact weight measurement may not be so critical for cowboy shooting but once you have worked up a load, it allows for a greater consistency than just filling the case X full and mashing a bullet on it.

So, to follow my own rules, I first set the powder drop by the desired weight of the powder being used and then measure the selected charge in the case to make sure it is getting the correct compression and everything is set up correctly. When using a scoop it will be identified by the name, granulation and scale weight of powder that it will hold when it is used to scoop from a container and leveled off. With this information I'm then ready for the loading session. That's my story and I'm sticking to it.

Modifying the Ejector in the H&R or NEF rifle to Extractor

Tue, 24 May 2022 04:43:08 GMT

THE TIP-UP RIFLE
Harrington & Richardson
Wesson & Harrington
New England Firearms

We often see a type of single shot rifle at SASS events, in which the barrel hinges down to expose the chamber for loading. This design was one of the most common of the 19th century. I believe there were over a dozen different makes of rifles that operate in this manner.

The correct term for this rifle design is “Tip-up”. Today we often hear them called “Top Breaks”. The trade name “Handi-Rifle” is also used as a generic term for the tip-up design. We are fortunate to have these fine single shot rifles made available to us at reasonable cost, allowing many shooters to enjoy the activities requiring a single shot rifle.

The H&R, W&H, and NEF in the many different models, have one small problem in common. That is the automatic ejector. If you wish to mount a tang sight on the rifle, the auto ejector will slam the empty cases into the sight each time the gun is opened. While SASS does allow the use of the auto-ejectors in Plainsman, and Long Range Single Shot, they are prohibited in the Buffalo Single Shot category! To make the greatest use of the rifle it is necessary to alter the auto-ejector to an extractor only configuration. Having done that, you can enter all SASS competition categories. Unfortunately, if you wish to shoot the really fun Plainsman events, you’ll have to shoot against the auto-ejector equipped tip-ups.

There were no auto-ejector guns of any consequence, with the exception of the Trap Door Springfield, used in the 19th century. Since the Plainsman event is timed, I consider it a gross violation of the alleged SASS standard of “Spirit of the Game” to allow the ejector guns in the event. I’ll get off my “soap box” now.

Whatever your reason, changing the auto ejector to extractor is a very simple job. Begin by removing the fore end screw, and the fore end. Remove the barrel from the receiver. Now examine the under lug. You will note the ejector, the ejector catch, and three roll pins. The rear most roll pin should be drifted out ( either direction ) until the ejector catch is free. I prefer to leave this pin retained in the off side of the under lug. In this way it won’t get lost and is started, ready to drive back in. If you now pull the punch out, the ejector catch will drop downward and the ejector will move outward. If the ejector does not seem to be free, just pull down a little on the end of the ejector catch. Figure 1. shows the parts I have mentioned as well as a second ejector that has been ground down. Modification of the ejector required about 5 minutes with the use of a common “Moto Tool”. Refer to the drawing in figure 2., to see what metal needs to be removed.

Figure 1

Figure 2

Remove Shaded Area

There are two springs in the under lug. They will not fly out, nor will the ejector ( nothing will go “sproing” and fly across the room ). In figure 1. you will note the pin punch, which is a 5/32” diameter. You will also see a #36 twist drill. To reassemble, insert the modified ejector into its slot in the under lug and press in against its spring. Now press the ejector catch upward into place and insert the drill bit in the pin hole. The drill bit will serve as a slave pin, to hold the ejector catch in place while you turn the assembly over and drive the roll pin back in place.

Presto! You now have an extractor only system! The ejector is a $10.00 part, and you may wish to pick up a spare before starting work. With the H&R/W&H converted to extractor, you have a very accurate replica of the 1880 Wurfflein target rifle.

Cheers
Old Scout

lees-gunsmithing

The Safe Capping of the Percussion Revolvers

Capping the Percussion Revolver

The Test Crew

Can a static spark set off black powder?

The question: Can a static spark set off black powder?

Why Does a Short-Started Ball Cause a Barrel Bulge?

The Question: Why Does a Short-Started Ball Cause a Barrel Bulge?

Measuring Black Powder

How do you measure Black Powder or it's many substitutes?

Modifying the Ejector in the H&R or NEF rifle to Extractor

THE TIP-UP RIFLE Harrington & Richardson Wesson & Harrington New England Firearms

THE TIP-UP RIFLE
Harrington & Richardson
Wesson & Harrington
New England Firearms