I never tried reloading or shooting with lead bullets, sounds like a whole new ball game. Gas checked Vs bevel base, which ones to get for my marlin guide gun?
Where can I find loads for lead bullets?
Any manuals or websites with load information?
My worst fear with lead bullets is the lead fouling in the barrel since in my mind lead is that much softer than copper and I imagine it smudging on the rifling.
First off, "lead" bullets are actually an alloy of lead, and are, to varrying degrees, harder than lead is. Don't worry about leading your barrel. In your shiny Guide Gun barrel, leading is an absolute nothing.
The cast bullets are the way to go with a 45-70; good accuracy and a much better price on them, as well as a great variety of heavy bullets, that work so well.
The gas check is used on cast bullets that are driven faster. I have used hundreds, at least, of plain, flat based cast bullets in the 44 magnum Marlin rifle. Leading the barrel was not a problem at full power loading, which would be in the 1700s of fps. However, at that speed, gas check bullets were a bit more accurate. Plain base bullets can only stand so much of a charge, before the pressure eats away some lead, and upsets the accuracy.
The accurate load I quoted for my 45-70 Marlin, which is probably about 1500 fps, is equal, whether plain base or gas check. Bevel base is only one pattern of a plain based cast bullet. Most of them are just flat.
With cast bullets you must have a sizing die that bevels the mouth a bit, so the cast bullet will seat, without shaving off some lead. If you do this, the key is to bevel the case very little, in the interest of making the brass last. I open the mouth just enough that I can feel it, when I slide my fingers over the case.
All of the 45-70 loads given on this thread, by various people, are away below the pressure limits for the Marlin. There is probably a bit less pressure with cast bullets, as compared to jacketed, for any given load. Therefore, any load you see in these ranges, that is for a jacketed bullet, can also be used with a cast bullet.