Some time ago, there was a thread here about scarcity of 41 Colt brass. I remember when I got a couple of those 41 Colt revolvers, brass was very scarce. I ended up buying a few boxes of the Winchester run of factory ammo (very expensive). Shortly after that, Starline started producing those cases. A friend of mine made brass from 38 Spl brass: You don't need to heat the brass red, just a straw/brown should be sufficient. Also, if you expand the neck in 2-3 short operations, turning the case between advancing each stroke, the neck will expand more evenly.
How to form low-cost 41 Long Colt cases
1. Start with .38 Special brass or shorten .357 Magnum brass. I used a Lee .38 Special trimmer in a power drill to speed it up (the difference between the length of the 41LC and .38 Special cases is only .030" and after expanding it is virtually zero).
2. Anneal the brass. I did this by inserting a long 5/16" steel rod in the mouth of the case, holding the case upside down, and rotating it in a propane torch flame starting from the center of the case and working toward the case mouth. When there was a noticeable change in color (brownish starting to turn dull cherry red -- bright cherry red or orange is too much), I dropped it in a bucket of water to stop the heat from migrating completely through the base (head) of the cartridge. Even if the head softens, this is not particularly dangerous at 41LC pressures. The primer pocket will expand on firing and make the case useless in one or two reloadings. After annealing, parts of the case will be discolored (brownish). This has no effect on
it and will lessen with each cleaning.
3. I put a .38 Special case holder in my press and screwed in a Redding 41LC neck expanding die (my wife bought me a Redding set for Christmas). The Ideal 310 nutcracker will work, but it is MUCH easier
4. Put the annealed case in the case holder and raise it into the neck expanding die. Do it gently and it will expand straight and even from 0.357" ID to 0.386" ID in the front 1/2" of case. Remove it from the die.
5. Roll the case on a flat surface. If it did not expand evenly all around, you will see it "wiggle" as it rolls. If it wiggles, throw it
out. The primer will not line up with the firing pin if it did not expand straight. There are VERY few crooked cases with the Redding die, but the Ideal nutcracker turns out more mistakes. It is because the hole for the 41LC case in the handle is larger than the .38 Special case and the case "tilts" easily. This is not a defect of the Ideal 310. It loads 41LC cases perfectly. That is what it was designed for. It was not designed for expanding .38 Special cases.
6. Prime the cases as usual. Use a .38 Special shellholder.
7. Add powder. I use 3.3gr of Bullseye in my 1892 Colt.
8. Seat a bullet. I use 185gr Rapine HB-RNL bullets which are available from several sources. You cannot seat it as deeply as normal. The neck expander is not long (deep) enough, so the expanded part of the case is too short. There are three lube grooves in the Rapine bullets. You can seat it so that two lube grooves are inside the case and one is outside the case. I just screw out the bullet seating bolt a little, but leave the crimp setting in place.
9. They look strange when you are done loading them. There is a larger diameter bullet and case in the front and a smaller diameter case behind that. Don't worry. You can load them in the cylinder without spacers in the rear or pointing the gun upward or anything else unusual. Just load them into the gun like you would any normal 41LC case and shoot them. If they are straight, they will fire, and they seem to be about as accurate as "real" 41LC cartridges even in the "pre-fireformed" stage.
10. What you have now is an expanded (fireformed) .38 Special case that looks just like a real 41LC case in the front 3/4 of the case. It gently necks down to a standard .38 Special rim in the rear 1/4. It is sort of like a large extractor groove for a rimless case. The 41LC is not really rimless, but it does have a VERY small rim. There is no longer any hint of where the neck expanding stopped and the fireforming started.
11. Reload them as normal 41LC cases from now on. Use a .38 Special shellholder. BTW, in spite of what the reloading companies say, a .38 Special shellholder will not accept a REAL 41LC case. You have to use a motodremel tool to open up the inside slightly (you don't need to do this for the formed cases). Don't overdo it. The 41LC rim is very small.
12. I have not had any cases fail during firing using this method. However, if you wish to do the same, you do it at your own risk (just like handloading is done at your own risk). At this writing, I have reloaded the first ones I fireformed ten or more times. Like any case, it will eventually crack at the neck from repeatedly forming, neck expanding, and crimping. However, it looks like they will last a long time at 41LC pressures. I have not had any let go (split) near the base.