Tuning the Pietta

Remington New Army Revolver

Mohave Gambler

Introduction to the Project
One of the most popular Cowboy Action cap and ball revolvers is the Remington New Army Revolver made by Pietta of Italy.  The reason for the popularity of this old gun is that it is very affordable.  New .44 caliber revolvers can be purchased for as little as $140, which makes it one of the best bargains in shooting today.  This is my fourth Remington revolver and my second in all-steel.  There are claims that the brass frame versions were used by the confederate army because of the shortage of steel in the southern states, but I have not seen any evidence that these revolvers were made in anything but steel. 

Figure 1.  The two Remington New Army revolvers used for this article.  The new one is on top and the old one is below.  The old one is in the "white" with bare metal and has been shot in matches in both California and Arizona. White guns tend to look a little larger than their blued counterparts..
The Remington New Army Revolver is often referred to as the 1858 Remington.  This is because the New Army Revolver is an evolution of the original Beals 1858 patent.  The current reproduction 1858 Remington revolvers are closest to the Remington New Army Revolver that was manufactured between 1863 and 1888.  I like to refer to these revolvers as the New Army model.
The New Army revolver was popular because of its stopping power and light weight.  The use of a top strap that turns the frame into an "O" shape provides a lot of strength for the amount of steel being used.  In addition, the barrel is screwed solidly into the frame of the gun and the rear sight is machined into the frame.  Once the New Army is properly sighted in, it will not change because of parts wear like the Colts.  The problem with the Remington design happens to be caused by the very tightness built into the "O" type frame.
The use of blackpowder in cap and ball revolvers results in a lot of unburned particulates being left over as a byproduct of the explosion.  These revolvers were designed to be used in battle and not immediately reloaded.  A Cowboy shooting match will typically put thirty shots through a gun in about three hours of shooting.  Colt revolvers seem to shoot much longer without becoming fouled by blackpowder residue and I have often heard it is because the are built to much looser tolerances.  This is not really true. 
A comparison of the Colt and Remington designs will reveal three significant design differences.  First is the absence of the top strap on the Colt allows the powder residue that leaks out of the barrel to cylinder gap to escape straight out into the air above the revolver.  The Remington top strap deflects some of the escaping residue back into the action at the front of the cylinder.  Second is the larger cylinder axle, or arbor, and it appears to be threaded, which provides a place for the powder fouling to be retained in a manner similar to the treads of a tire.  The Remington has a smaller cylinder that is smooth and provides no place for the fouling to go but between the moving parts.  Third is the fact that Colts have a gap between the cylinder and the frame that allows most of the powder fouling to escape out the side of the frame.  The Remington has a gap between the cylinder and frame that is in alignment with the barrel to cylinder gap.  This allows powder fouling to be forced between the cylinder pin and either the cylinder or the frame.  The result is a cylinder that does not want to turn.

Let's Begin
I like to begin a project by evaluating what I have and then establishing my objectives and outcomes.  I started by doing a visual inspection of the new gun and found minor rust throughout the internal sections of the frame, inside the cylinders, in the housing area for the hand, and on the cylinder pin.  One of the wood grips had a very minor chip in the curved area just to the rear of the trigger guard.  The hand spring does not fit properly and allows the hand to be very loose.  An inspection of the gun's timing shows that the hand is too long, which is confirmed by the fact that metal at the tip of the hand is already wearing away where it binds against the star.  There is a lot of roughness in the hammer cocking and the loading lever seem to be binding a little.  I estimate the trigger pull to be around ten pounds and the hammer cocking to be close to 25 pounds.  The greatest potential problem is with the barrel to cylinder gap, which measured in at .003 inches.  My more successful revolvers tend to measure about .010 making this gun the tightest cap and ball revolver I have worked on. 
Goals and objectives:  I want to use this revolver as a the mate for another Remington New Army revolver that I have shot in competition for about a year.  It will be the replacement for a similar model that has a brass frame.  In order to shoot a pair of revolvers, they must either be set up identically, or be enough different that I can easily tell which is which.  This gun will be modified in two separate projects that will be documented separately.  The first phase will be to demonstrate how to take the standard revolver and rework the parts enough to make it operate much more smoothly.  The second phase will involve more radical modifications that will continue to improve the functionality of this fine revolver by adding coil springs, a gas ring, a dovetailed front sight, and new grips.  I will attempt to make the gun operate properly without opening up the barrel to cylinder gap, because I want to test my theory that opening the gap only allows more fouling to escape and compounds the binding problems.  For the purposes of this article, I will be including photographs from both the new blued revolver and a second revolver that I have that is bare metal.  The bare metal is easier to photograph and will make it easier to document some parts of the project.
Let's start with the disassembly and final inspection of the revolver.  We begin by making sure the gun is not loaded.  I visually inspect each nipple to make sure there are no percussion caps installed on any of them.  I then lower the loading lever a little and slide the cylinder pin forward so I can remove the cylinder and inspect each chamber with a flashlight.  I want to see the nipples at the bottom of each chamber to assure myself there are no charged cylinders. After assuring the gun is not loaded, we remove the grip panels by removing the screw that holds them together. 

Figure 2.  The Remington New Army has been taken completely apart and is almost laid out as an exploded view, but without the screws. This shows how simple this gun is and how easy it is to work on.  A basic set of gunsmith's screwdrivers and a nipple wrench is all that is needed.
Continue taking the gun apart by removing the mainspring tension screw at the front of the lower grip frame.  With that out, remove the hammer spring by sliding it out of its retaining slot.  Remove the screw on the left side in front of the cylinder that holds the loading lever in the frame and slide the loading lever assembly out the front of the ram slot.  Turn the gun over and remove the trigger guard screw and remove the guard by lifting away from the frame and pulling slightly forward.  Remove the trigger/bolt spring by removing the screw that is just to the rear of where the trigger guard housing screw.  Turn the gun so the left side is up and remove the trigger retaining screw and slide the trigger and cylinder bolt out the bottom of the frame.  Remove the hammer retaining screw from the left side of the frame and slide the hammer down through the area of the trigger guard until the hand retaining screw is visible at the bottom of the frame.  Remove the small screw that retains the hand and slide them out.  The hammer can now be moved up and removed through the top of the frame.  This completes the complete tear-down of the gun.

Figure 3.  This photo shows the hand channel . It rises from right to left and you can see metal about half way up that will obstruct the hand spring. Photo on right shows the hand channel cleaned of the casting material.

Carefully examine the photos in figure 3.  The photo on the left shows the hand channel that runs from the left side of the hammer and up to where the hand presses against the star at the rear of the cylinder.  The barrel is pointing up in this photo and the picture was taken looking up through the removed trigger guard.  Note the amount of flashing located about half way up the channel?  It resembles a speed bump and the hand rides in this channel with the leaf spring trying to slide right through that flashing.  We should begin by polishing the channel enough to let the hammer operate in a reduced friction environment, but it will be difficult to remove that metal up in the channel.  One way to remove the metal is with a cold chisel, but those are too big.  In the past I have removed this metal flashing by using the tip of an engraving tool.  One of the best tools for polishing up in these tight areas is a piece of brass purchased at the hardware store.  I found a piece that is about ten inches long, one-quarter inch wide, and about .160 thick.  This brass can be filed to fit into the recesses of the gun and emery cloth can be glued to the brass to make a file for reaching in to file these recesses.  Old hacksaw blades could also be ground down to serve this purpose.
The photo on the right shows the hand channel from a slightly different angle.  The speed bump has been removed and the hand spring can smoothly run through that area.  This will provide a smoother feel while cocking the gun and will reduce wear and friction on the hand spring while shooting. 
Now we move our attention to the sear.  The sear is a critical component in the feel of the hammer and trigger pulls.  Roughness on the ramps leading to the half-cock notch or the sear can make the hammer feel gritty and rough.  Smoothing the high spots from these ramps will make the hammer pull feel very smooth, but does not really affect the smoothness during firing because the trigger is not in contact with these areas when the hammer is falling.
The amount of stoning and polishing needs to be addressed.  The purpose of stoning is to reduce friction and to make the moving metal parts move against each other without having to follow a rough contour.  Taking the metal down to a mirror finish can help the action, but polishing the machine marks until they are even reduces the chances of cutting through the case hardening and allows little recesses to hold some lubricant.
The sear depth and angle are import to the feel of the gun and represents the potential to make the gun unsafe.  Everything is a trade-off between feel and strength.  A shallow sear will allow a quick break with little trigger movement (creep), but may not catch properly when being cocked and slight wear or damage on the edge of the sear can cause the sear to become unreliable and may allow accidental discharges.  The fact is that creep tends to only be a problem when someone is feeling the action and is hardly noticeable in action shooting.  I like to set the dept of the sear at .030 inches, which is about the dept I have found on most Remington reproductions.
The sear angle is also important in the feel and safety of the trigger.  When the trigger and hammer sears interlock, if the sear is on the radius line of the hammer, then the angle is zero or neutral.  This means that the movement of the trigger does not move the hammer at all as the trigger is being pulled.  A positive angle means that pulling the trigger causes the hammer to be cocked slightly more as the sear must move the hammer in order to clear.  This slight dovetailing of the sears should be at around 2-3 degrees to provide a crisp trigger that will be safe and hold well.  Any greater angle is an over-engagement and creates an excessive trigger pull. A negative angle is unsafe because there is no interlocking of the parts and the trigger can release the hammer without being touched.

Figure 4.  The hammer sear at left has only been lightly buffed to bring out the machining marks.  The one on the right has had the machining marks smoothed and the sear has been squared better.
The photos in Figure 4 illustrate the change provided by reworking the hammer with an Arkansas stone.  The half-cock notch is cleaner, the ramps are cleaner, and the sear is cut to about a three degree angle and is .030 in depth.  The work is not perfect, but is a significant improvement over the original sear and it provides a crisp and clean break in action shooting. This is a very precise process and the hobby gunsmith will get a little better with each sear that is polished.
Whenever working on the sear, I recommend that the hobby gunsmith reassemble the gun and test the trigger for safety.  Put the gun back together without the cylinder.  Cock the gun to half-cock and then put pressure on the hammer and try to push it back in the direction of the frame.  It should not move at all.  Assuming that the hammer holds well in the half-cock position, pull it back into the full cock position and repeat the test by pushing on the hammer to make sure the sear is engaging and holding.  If hard finger pressure on the hammer causes the sear to slip, then your gun is not safe and the sear angle is probably negative or the sear is way too short.  You should find the break to be crisp and clean.  If you are used to cartridge revolvers, the trigger and hammer pull may seem a little strong, but this is normal in a cap and ball revolver since the hammer must place pressure on the cap during ignition.
Hardening the hammer parts.
After polishing the various parts and reassembling the gun, it was time to take it to the range and test fire it to see how many shots could be fired with the .003 barrel/cylinder gap before the gun locked up from powder fouling.  I was shooting a CAS match that weekend so I took it with me for the test firing.  I did not think it would make it to the fifth shot, but I was very wrong.  I loaded the gun with about 25 grains of FFFg Goex blackpowder with a dab of Crisco in front of the ball.  The gun fired smoothly and accurately for all five shots without any indication of fouling  or problems.  My inspection of the gun showed it was very clean. 
This test defied conventional wisdom that a gun this tight would continue to shoot an entire cylinder of reasonably hot loads without any binding or problems.  I wish I could have kept firing the gun until it bound up in order to find out exactly how much it could handle. My theory is that the unusually narrow gap prevented much in the way of gasses and fouling from escaping between the barrel and cylinder.  This prevented gasses from getting into the cylinder pin and causing fouling jamming.  Measurements of my 1847 Walker and my two 1851 Navy Colts revealed that they were similarly tight with gaps of .002-.003. 
 
 
 
 

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