Loading Ammunition for the .45 Colt 1860 Colt Conversion Revolver

Edit 28JUL2023:
I have recently acquired a custom mold from Accurate Molds which produces a bullet that is much closer to the design of original .45 Colt ammunition (see the link HERE) to replace the RNFP Lee bullet mold I was using previously.  This mold is of superior quality, and it significantly changes the cartridges so I have updated this post to reflect that change.

Colt 1860 Cartridge Conversion Revolver with Frankford cartridge packets and loose rounds.

Introduction
The .45 Colt cartridge was developed jointly by Colt’s Patent Firearms Manufacturing Company, of Hartford, CT, and the Union Metallic Cartridge Company of Bridgeport, CT, and was ready for testing by 1872.  The M1873 cartridge had an internally lubricated two-groove, hollow-based, soft-lead bullet that weighed 250 grains over 30 grains of 2F (not 3F as we would expect) black powder.  These first military cartridges used the Benet priming system which held priming compound between the case and a small brass insert; from the outside they look like rimfire cartridges, but aren’t (see the schematic below), although external primers were used in some commercial cartridges.  These cartridges are impossible for me to duplicate, so I use regular Boxer-style primers as in the civilian case also depicted below.  Later military cartridges lightened this charge to 28 grains of 2F black powder under a 230-grain bullet, and the M1882 et seq. used an external primer rather than the Benet style (Kuhnhausen, Jerry, The Colt Single Action Revolvers. McCall, ID: Heritage Gun Books, 2001 p. 23).  The M1875 cartridge had a muzzle velocity of 730 f.p.s. with a 235-grain bullet for a muzzle energy of 278 ft-lbs. when fired from the Colt Single-Action Army (id. p. 15).

Original cartridges.

My.45 Colt Load

My original .45 Colt bullet was a 250-grain Lee RNFP that I cast in soft lead and pan-lubed in a historically correct mixture of beeswax and tallow.  I was unsatisfied with them because they were not a good match for the originals (as shown above).  I loaded these with 35 grains of 3F powder in Starline brass with CCI large pistol primers.  The average muzzle velocity of of these cartridges was 788.1 f.p.s., giving a muzzle energy of 345 ft-lbs. when fired from the 7.5 in. barrel of my revolver.  This is somewhat faster than the 730 f.p.s. for some of the original cartridges.

The new bullets came out of the mold at 265 grains when cast with pure lead.  Obviously, that is much heavier than the originals, so I switched to casting with a 20:1 tin alloy which brought my average bullet weight down to 257 grains--slightly heavy, but closer.  My first batch was loaded with 35 grains of 3F powder, but the next batch will be loaded with 30 grains of 2F powder to try to match the performance of the M1873 cartridges pictured above.  I will compare the ballistics of both loads with the information I have about the originals in order to decide on my "final" load.  It must be understood that I am not working for the most accurate load, necessarily, but rather for the load which is as close as possible to the original ballistically.

This picture shows one of the new bullets compared to the diagram of an M1873.  As should be obvious, it is a very close match with two differences:  First, the original bullets didn't have a crimp groove, and they had a hollow in the base.  Less obvious is that the originals were .452 in diameter, while mine are .454.  The originals were made that size to make loading them into the cases easier using the machines of the period, and this reduced size was the reason for the hollow bases, which helped the bullet obturate more to fit the bore.  Since my bullets are slightly larger they don't need the hollow base.

Comparing my new bullets with an M1873.

One of the new cartridges with a package of its fellows.

Loading Procedure
1.  I have covered the procedure for casting and greasing bullets extensively in other blog posts so I won’t go over it again here except to say I pan-grease the bullets in an 8:1 ratio of lamb tallow and beeswax.  The bullets come out of the mold at .454 in. and I do not size them.  (NB:  Most of the pictures below show the older RNFP Lee bullets unless captioned otherwise.)

2.  After shooting I immediately soak the shells in a mixture of white vinegar and water for ten minutes to neutralize the salts from the black powder, then I soak them in a mixture of hot water and dish soap for an initial cleaning.  I then tumble the shells to clean them completely.

Starline brass.

3.  I use a Lee progressive reloading press and a set of Lee carbide dies, which includes a sizing and de-capping die, a powder-through case mouth expansion die, and a bullet seating and crimping die.  There are several other kinds of die sets available, some with separate dies for bullet seating and crimping—follow the manufacturer’s instructions for them.  Be sure to insert the shell holder into the slot on the ram before loading in order to hold he shell securely during the loading process.

Before starting to load it is necessary to set up the dies.  Here are videos from Lee showing how to do so:
Sizing and de-capping die:  https://youtu.be/VKRkNWbHKwc
Case-mouth expansion die:  https://youtu.be/7j2I2FEZKsM
Crimping and bullet seating die:  https://youtu.be/lF5h5GyzyKQ

Lee die set:  Three dies, priming tool/capper, shell holder, and 2.2 cc Lee dipper.

The key to setting up the dies is to follow the instructions carefully and to start with the most minimal positions for each die, then adjust the position of the die in very small increments.  Adjust the die, try it, check the result, and make very tiny changes, trying the result each time until you get exactly the results you want.  Making big adjustments can result in your brass being worked too much, which can cause it to fail, or flared too much, which can cause the brass to be damaged by the next die.  I start with one shell, checking each stage of the process and making sure it’s perfect before tightening down the die and going on to the next stage.  I don’t start regular rapid production until I have the dies perfectly set and locked down and have produced one perfect cartridge.

The Lee loading press set up with all dies in place.

4.  The sizing and de-capping die reshapes the entire shell body which will have expanded when fired and also de-caps the spent primer in the same action.  Although I use carbide dies, I still lubricate each shell very lightly before starting.  If your dies are not carbide, lubricating the shells is important to prevent them from becoming stuck in the die.

A shell in the shell holder ready for loading.

5.  I have a capping tool which fits onto the shaft of my reloading press.  When the ram is fully raised to size the case, I insert a primer into the cup on the capper with the open end of the primer facing up.  Then I lower the ram which moves the capper under the shell and press the ram down very firmly to seat the primer.  I raise the ram up slightly and check to make sure the primer is no longer in the capper, then remove the shell and run my finger along the base to ensure that the primer is seated properly.  The primer face should be just slightly below the base of the shell or it may catch on the wall of the revolver and prevent the cylinder from rotating properly.  If it isn’t right, I just lower the lever again and set it a bit more firmly.

The ram fully up into the resizing die and a primer in the capping tool.

Checking the seating of the primer.

6.  The case mouth expansion die opens the case mouth very slightly to allow the bullet to be settled into it.  Flare the mouth of the case the absolute minimum possible; the bullet should just barely fit into the top of the case mouth.  Too little flare and the bullet may get shaved by the seating die; too much flare and the seating die may crumple the shell edge, making it unusable.  The bullet only needs to sit a small fraction of an inch inside the case mouth—no more.

The Lee expansion die is open from the top, so I put a powder funnel on it then pour a measured charge of powder down through into the shell while it is still in the die.  I use a Lee 2.2 cc dipper which measures 35 grains of 3F powder.  After dumping the powder I tap upward on the lever of the press a few times to ensure all of the powder has gone into the shell.  Some brands of dies do not have this feature, so if you have one of these you will have to remove the case and fill it with powder before proceeding.  After pouring the powder I lower the ram and look inside the case to make sure the powder is actually in it and that it looks about right.

Adding the powder through the powder funnel.

7.  With the ram fully down, I insert a greased bullet into the case mouth, trying to ensure it is not canted off center.  I then drive the shell up into the die, which will seat and crimp the bullet in one step.  A certain amount of crimping is essential or else the bullets may walk themselves out of their shells because of the recoil when the revolver is fired.  There is a degree of controversy, however, as to how much crimping is necessary.  Some experts argue that you should crimp just enough to hold the bullet in, and no more, since the more you crimp the more you work the case mouth, which can cause it to fail sooner.  Others argue that while that is true when shooting smokeless powder, when shooting black powder (which I do) a more significant amount of crimping is called for to give the powder time to produce enough pressure before the bullet starts to move.  Exactly how much of a crimp you want will require some experimentation, but generally speaking you want enough to roll over and completely cover the crimp ring on the bullet, but not so much that it digs into the lead and cuts another groove.

A bullet set into the flared case mouth.

A seated and crimped bullet in the cartridge.

Inspection
When I have completed a cartridge, I wipe it carefully with a rag to remove any excess lube or grease, then inspect it carefully.  I look for any ballooning of the case, to see whether the primer has backed out at all, to see if there are any cracks of flaws in the brass, and to see that the crimp looks good.  After that I measure the overall length of the cartridge with a caliper because the bullet may protrude from the cylinder and prevent it from rotating if the OAL is too great.  While the maximum length of a .45 Colt cartridge should be 1.6 in. or less (according to the Lee load data), your revolver may require something shorter, so check to be sure.  I set my bullet-seating die so that the overall length I get is 1.56 in. exactly; this seems to work well for me, and puts the crimp right on the crimp ring of the bullet; again, with other bullets your experience may differ.  I also insert each round into the chamber of a cylinder (after removing it from the revolver) to ensure it fits correctly and isn’t swollen at any point.  I inspect and measure every single cartridge because although it’s tempting to just crank them out your dies may move slightly during the loading process which could cause a bad result.  Take your time, be careful, and check your results—bad ammo can be very dangerous.

Measuring and inspecting the finished cartridge.

Finished new-style cartridges ready for packaging.

Packaging
As readers of this blog will know, it’s not enough to make the ammunition, it also has to be packaged correctly.  I have a reproduction 50-round box for cartridges, but I find it to be something of a pain.  It looks good and is convenient, but after firing a few cylinders the loose cartridges start to just roll around in the box.  To get around this problem I made a set of smaller 12-round boxes to copy those issued by the Frankford Arsenal, and I find they work much better.  I measured a single round and used those measurements to design a box pattern which I print, glue to a piece of light cardboard, then cut out.  I glue the box together, insert the cartridges (with a piece of cardboard between the rows), close the box, and wrap it with a wrapper I designed to match the originals.  The original wrappers were shellacked after being wrapped, but I don’t bother with this step since I don’t shoot in the rain.

An original Frankford Arsenal package from 1874.

My custom box loaded with 12 cartridges.

The cartridge package in its wrapper.

Disclaimer
This essay is not intended to teach anyone how to load ammunition, only to show how I do it for my revolver.  Loading ammunition incorrectly can cause serious injury or death, so do not rely on anyone else for information about how you load your ammunition, always rely on the recommendations of your firearm manufacturer and on officially published load data rather than on the words of some random stranger on the Internet.  Every firearm is different, and a load that works well in one revolver may not work well in another and every component can affect that load.  Learn to take responsibility for yourself and not to blame others for your actions.