Howdy
Since my name was mentioned, I might as well chime in on this topic. I have been loading 45 Colt, 45 Schofield, 44-40, 44 Russian and 45 -70 with Black Powder for quite a few years now for Cowboy Action Shooting. My method is the same for all of the 'pistol length' cartridges, but I do things a bit differently for 45-70.
Here is a photo tutorial I put together a few years ago showing the method I use to determine the proper amount of powder and compression when first setting up to load any particular cartridge and bullet combination. Yes, I do load specific to the bullet. Basically, you will get a different amount of cartridge capacity in the case depending on how deep the bullet extends into the case when seated and crimped. Generally speaking, I only use one bullet style for each of those cartridges, so I only go through the exercise once. If I were to load a second bullet style in any cartridge, I would go through the exercise again for that cartridge. It is pretty simple, only takes a few minutes to do.
http://www.cascity.com/forumhall/index.php/topic,18257.0.html
My method using Black Power (real Black Powder, not substitutes) is to set my powder charge so that the powder is compressed between 1/16" -1/8" when the bullet is seated and crimped. Yes, you can add more powder and compress it enough to allow the bullet to seat and crimp. This is the only way to duplicate the original 40 grain load that was used in the early Benet primed, copper cased, folded rim cases that were originally used with the 45 Colt cartridge. Modern cases do not have as much case capacity as the old Benet primed cases or the later balloon head cases. So stuffing in 40 grains means a lot of compression, maybe 1/4". This is a very stout load, and in This Cowboy's Humble Opinion, it is overkill, and a waste of powder.
Using my method, I put in between 33 grains, and 37 grains
depending on the brand and granulation of powder I am using.
Regarding weighing vs measuring Black Powder by volume. I wish I had a dollar for every time I have read or heard that you must load Black Powder by volume. The simple fact is there is absolutely nothing wrong with weighing Black Powder. I have done it myself many times.
But the fly in the ointment is that not all Black Powder weighs the same. It ain't like producing Smokeless powders, where the manufacturer strives to make the powder with exactly the same burn characteristics lot after lot and year after year. Black Powder manufacturers use techniques and materials that may vary slightly from manufacturer to manufacturer. There is no industry standard to exactly what the burn rate and density should be from manufacturer to manufacturer. So Brand X powder may weigh a significantly different amount than Brand Y powder. I keep a chart in my reloading notebook of the actual weight of the charges I use in all the cartridges I mentioned earlier. As an example, I have settled on 2.2CC of FFg under a 250 grain Big Lube bullet in 45 Colt. According to my notebook, the actual weight of that charge is 34.5 grains when using FFg Goex, 37 grains for FFg Elephant, and 33 grains when using FFg Schuetzen. So one can see that saying XX.X grains of FFg is meaningless unless the actual brand is specified. Not specifying the brand and granulation of powder could possibly result in too much or too little compression. To make matters worse, the weight of the powder seems to vary slightly from year to year or even from lot to lot even with the same manufacturer.
The upshot is I am actually measuring my powder by volume, but I also have a reference number written down for how much the charge actually weighs.
Not to worry, you cannot stuff enough powder into a case designed for Black Powder, such as the 45 Colt, to damage a revolver in good mechanical condition and made with modern steel.
Yes, you may get different velocity with different brands of powder using my method, but frankly, for CAS it is not enough to worry about.
However when I load 45-70 for precision long range accuracy, I do limit my choice of powder and amount of compression. And there are some BPCR competitors who actually weigh their powder, they do not measure by volume. But you can be sure they have qualified the exact brand, granulation, and lot of powder they are using, and if they buy a new batch of powder they will requalify it.
I don't even want to get into the grains vs 'grains volume' can of worms here.
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One other thing that I don't think has been mentioned here, if you shoot real Black Powder you are going to have to do something about the lube on your bullets. Generally speaking if you use modern Smokeless lube, the stuff that comes on most cast bullets, you will have problems with Black Powder. Generally speaking, using Smokeless lube with Black Powder will result in hard caked fouling in the barrel that will quickly ruin accuracy and be difficult to remove. The bullet in my photos is a Big Lube 250 grain PRS bullet lubed with SPG.
Somebody mentioned melting the lube out of regular Smokeless bullets and substituting a BP compatible lube. This is called Pan Lubing. I used to Pan Lube my bullets with a 50/50 Beeswax/Crisco mix for a number of years before changing to Big Lube bullets. Here is something I wrote up about Pan Lubing a few years ago:
http://www.theopenrange.net/forum/index.php?PHPSESSID=8f96e06c3875aa962798abd013cd1595&topic=301.0
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Reduced loads and fillers: Some years ago I did use corn meal for a filler in some of my 45 Colt loads. I had no problems at all. Currently, the favorite filler in the Cowboy Crowd is Grits. I know some guys are using Cream of Wheat too. I have never heard of using Walmut Media, but I guess there is a first time for everything. 'Rebound' is not how I would characterize what can happen with fillers. Using grain products as a filler, overtime they can absorb moisture from the surrounding atmosphere, even though the bullet is seated and crimped. Over time, the theory goes, as the filler absorbs moisture, it will attempt to expand, but being locked in place by the bullet it cannot. So the slightly damper filler can raise pressure when the cartridge is fired. That is the theory anyway.
A very different phenomenon can happen if one attempts to put a really big load of powder under compression and seats and crimps bullets in two steps. It is possible for the compressed powder to push the bullet out a bit in the time between seating the bullet and compressing it. A friend of mine was stuffing a standard amount of powder and a wad into his 45 Colt loads without reducing the amount of powder to allow for the volume of the wad. He was having problems cycling these rounds through his Uberti 1873 replica. They were too long and were jamming the gun. He was seating and crimping in two steps on a progressive press. Just the few seconds between seating and crimping was enough for the powder and wad to push the bullet out a bit, affecting his cartridge Over All Length. When he reduced the charge a bit, the problem went away.
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I stopped using filler a long time ago. Instead, if I want lighter loads I will go to a smaller case with smaller capacity. For a light load in a 45 I will load the 45 Schofield round with 1.9CC of FFg and a 200 grain bullet. A much milder load than my standard 2.2CC/250 grain 45 Colt load. However, as with all things there is a catch. Sometimes a 45 Schofield round will not chamber properly in a Ruger, because of the larger diameter rim, and the way Ruger machines the ratchet teeth on their cylinder. Not every time, but I do have two Vaqueros that are a bit stubborn with one chamber each when loading 45 Schofield in them. I have had no such problems with Colts or clones, the ratchet teeth are machined differently and have a tad more clearance.
The 45 Cowboy Special can also be used for very light Black Powder loads in a 45 Colt revolver. It has the same internal case capacity as a 45 ACP, but the same rim design as the 45 Colt.
http://www.cowboy45special.com/
