Screwbolts, your answer contained exactly the info. I was looking for...thanks. I tried the smooth green Harvester sabots that comes with the 280 gr. 44 cal bullets, but they are extremely hard to get down my bore. Then I tried the crushed-rib green Harvester sabots for 44 cal. bullets and they were too easy to push down. So I tried wrapping the bullet in paper before inserting in the sabot and that worked but it's a picky process.

I've read that what you said is correct -- the thinner the sabot, the more accurate the load is likely to be. So I'll try the 280 gr. (44 cal) Harvester hard-cast in a sabot meant for 45 cal bullets by knurling the 280's up to a tight fit. Great idea.

I like the Harvester hard cast bullet approach because even if the shot angle isn't just right, the penetration is there regardless. To put icing on the cake for me is that they work best with light powder loads and that is means less recoil which is what I'm after.

The larger meplat on the 280 gr. Harvester hard-cast should be more effective on game than the smaller meplat of their 330 grainer, right? I say that because a wider meplat puts more of the bullet's weight forward and that makes for more stability on impact from what I read. Plus the lighter bullet will yield lower recoil. So if I can make the 280 work, that's my choice. But I'll try both weights and see which gives best accuracy with 75 to 80 grains of BH209.

About SR 4759: I'd use it instead of 209 if it were legal in MI for the zone I hunt. I notice that 209 puts out much less smoke than 777, etc. (hmm, since I have some old 4759 laying around I wonder if a conservation officer would notice if I used 4759 instead)

I see what you mean about barrel length, but don't think it ought to be that way in that the forward end of the breech plug is akin to the bolt face on a cartridge rifle because that's where the powder/bullet column starts for both systems. Well, OK, the head of the brass cartridge case is in there too, but that's not much more. The 22" barrel on my Model 70 Winchester 7-08 measures 21 and 7/8" and that's virtually the same as the advertised length of 22". Evidently that's not the way it is with muzzle loaders, but seems to me it ought to be.

Thanks again for all your good information.