I konw that under charged loads can result in either barrel blockage, or action failure, and that powder "separation" will severly mess with chamber pressures, but how low can a cartridge safely be reduced?
I'm working on a wildcat, and am not sure if one powder will be "too fast" so i'm asking if or how much can the load be reduced to "safely" get the pill out the tube without the action getting lodged in my cheek. (or having to rebarrel a new action)

and for info- quickload software calculated it as "acceptable" but i've had other people tell me otherwise.

What are you trying to do? There is a pretty extensive article in the NRA Handloading book that explains how to develop a gallery load. It in effect says to take a fast burning handgun powder from a load manual and cut it in half, then fire a round. If that exits, cut the load in half again. The idea is to stick a bullet in the barrel of a revolver. Once you are there, you work up in a couple of tenths at a time until you get one that just barely clears. Does this help?

slightly, but it's a large bottleneck cartridge.

Ttail Boss will allow you to load about any cartridge between 900 to 1000 fps if that is what you are looking for...

SR-4759 will allow you into the same ranges. Lyman 49 lists Cast Bullet loads for most rifle cartridges and my old speer manual has sr4759 loads for all calibers and jacketed bullets (if the cartridge existed when the manual was published).

I have trail boss as well, but, seem to do better with the 4759 for accuracy. My OPINION only.

thanks rc

oh, for more clarification, i'm not trying for a slower load, i'm going for "less risk of presure fail" on a faster burning powder.

H4895 can give you a very wide working pressure range. Look here. http://www.hodgdon.com/PDF/Youth%20Loads.pdf Start low on the powder charge and work up as with any new reloading.

There has to be a wildcat close to yours. Checkout the list here. Huntington Measure your case capacity, then google the wildcat for data. Or go by outside measurements like here > http://www.stevespages.com/page8d.htm

Do these numbers look ok?

or is this "too low" a load?