looking for a blackpowder load to shoot in my 45 colt Ruger Blackhawk.also need to know best way to assembel the load(never done any b/p reloading)  thanks   jwr

A couple of points first.

DO NOT LEAVE ANY SPACE UNDER THE BULLET!  By that I mean, you must fill the case volume completely, to the base of the bullet. Best results are with some compression of the load.

In modern, solid head brass this works out to something around 30g volume of FFg black powder. You might get 35g in if you use a loading funnel and really compress the load in seating the bullet. A good roll crimp and magnum primers help ignition and burning of the charge.

Also, I'd recommend getting some SPG lube if your are casting and lubing your own bullets. If not, there are a couple companies who sell lead bullets with SPG lube (Bullet Meister is one) which is specifically designed for black powder.

Obviously, you need to clean the gun (inside and out) thoroughly as soon as you finish shooting. The old stuff is great fun but terribly corrosive.

The original load was 40g in a balloon head case behind a 255g soft lead alloy bullet. It produced an honest 910 fps from a 7.5" barrel and is quite a handfull to shoot. You'll get a kick out of it and tast a bit of history in the process. Good luck!