Greg - I'd like you to be wrong on this one, though you seem quite knowledgable.
I don't think our Wyoming bituminous swells much. I also get zero bridging in my hand-fed. It burns quite clean, and only forms small clinkers occasionally. It doesn't turn "sticky" as some describe bituminous doing. Not really sure what that would even look like.
Our Harman dealer http://www.portersmvs.com/stoves/coalstoves.html
sells Magnum stokers (as well as Mark III, TLC2000, etc), and I have a question into them on the feasibily of using these stokers for our coal. I'll post their opinion/experience when they reply.
I almost bought a used Leisure Line stoker from a person here in Wyoming. He said it burnt the coal fine, except that you had to scrape the tar off the ramp every few weeks or it would burn back into the hopper. But it fed across the bed fine. He said it burnt back into the hopper 3 times in the years he owned it. I didn't like that possiblity, so I let it go and built my own handfed. It's working fine (except for a few issues you've helped with). I can just see myself moving to a "girlie-man" stove if feasible someday. There are a few Leisure Line dealers around too, so it seems that some people must be getting them to work.
What I'm hoping is that the "verti-flow" design of the Harman would prevent burn-back into the hopper, since the coal is being fed from a point lower than the bed/fire. Does that differ from the LL stoves? Don't the LL stoves bring the coal onto the ramp from above?
Seems like Berg (who originally started this thread) isn't frequenting this forum anymore, so I'm on my own. I'm sure his coal in Utah? is different than mine anyway. I'll find out if other Wyoming Harman customers have tried it.
What makes the underfeed stokers like the Combustioneer work with bit. coal? Wouldn't the coal coming up into the pot swell as well? Or is there enough agitation/mixing action to keep the coal from clumping/sticking? And is the mixing what causes the clinkers? Could a stoker ramp be built for a Leisureline or Harman that had tapered walls, allowing the coal to swell without jamming the grate? Or possibly a mechanism under, beside, or above the ramp that mashed or rolled the coal to keep the bridging/sticking from occuring? Or how about instead of a flat bed with holes drilled in it, using a series of bars for a grate that the coal had to "bounce down"? If that's too much agitation, then what about building a revolving grate/bed that the coal dropped on? I'm full of questions aren't I?
Just some thoughts - feedback would be great.