I am thinking about reloading .45 long colt black powder. My question is how mucch powder is recommended for the shot. Should I use filler to take up the empty space.
Don't leave empty space. Use enough powder to be compressed under the bullet without non-powder junk in your ammunition. That will give you the real frontier feel.
Step 1. Obtain empty .45 Colt case
Step 2. Fill case to just below the mouth with fffg or ffg blackpowder of your choice
Step 3. Place 250 or 255 grain bullet that has black powder compatible lube of your choice in the lube groove on the case mouth opening. (note: the bigger the lube groove in the bullet the more lube the bullet will carry, and the better it will work in a rifle)
Step 4. Seat bullet to crimp groove and crimp
Step 5. Repeat steps 1 through 4 till you run out of either a. Empty cases; b. Black Powder; or c. Bullets.
I'm using the .452" Lee 200 grain bullets for lighter recoil and 30 grains of FFFg Goex.
Loading it with 30 grains and 255 grain .452" bullets is really stout in my Remington '58, but it's okay in my Ruger OA.
ClemBert & Fingers McGee are spot on. What I found though was the recoil from those loads is substantial to say the least, not to mention 40gr of powder will eat up a pound of powder quickly.
I'm a big proponent of "Gallery Loads" for 45 Colt. For reduced recoil you can use 20gr 3f and then top off the brass with filler. Seat a .454 round ball and lightly crimp at the equator of the ball. You will probably want some lube around the edge of the brass before seating the ball, I was using SPG sticks and they work good.
Since then I've changed over to using EPP Ultra Gamer 150gr RN bullets that are pre-lubed for Black Powder. Less steps to the reloading process and they shoot great.
The process I outlined is the easy-peasy way to do it. Filling the case to a level where a 250 gr bullet barely compresses the powder will result in about a 30 grain load of fffg. While not a gallery load, it is very manageable.
In truth I'm JUST CHEAP!! I load cartridges with Swiss and they just don't give the stuff away. I have switched over to Goex for the 45 Colt Gallery Loads though and I don't see any difference as far as cleaner.
The one thing that none of us has mentioned is NOT re-sizing 45 Colt brass after it's fired with Black Powder. So far I've got some brass that has been loaded a dozen or more times with no re-sizing and it fits roughly the same as some of my newer stuff.
I found that not re-sizing cut down on the "Blow Back" in the cylinder considerably thus reducing cylinder related fouling.
Don't give away all the secrets at once!
The original black powder loading tools that I have seen didn't have case sizing, and I never size my BP cases either. More accurate, and as you said, less chamber and breech fouling.
I use a 1.9cc Lee dipper, which is about 30 grains, then a .060 wad, then a dollop of lard or Crisco, and a 250 grain cast bullet. I haven't found any need to sandwich the lube between two wads.