Carroll B
I have not read all the answers posted above but yours caught my attention... I have a question are you damp patching between shots? If so, what are you using?
I have two Omega's an older SS model and a new Z5, in both of these guns I am able to load HPH-24 sabots and either a .451 Noslers or .458 Noslers with the MMP Orange sabot, I should also tell that i also load 10mm 200 grain XTP's in the blue MMP sabot. They all load snug but not that I have to pound them down or can not push them down with one push on the ram-rod. At the range I use any or all of these without any problems - I do patch the barrel with regular windex after each shot. There is a hint of a 'crude ring' at the bottom of the barrel but not enough that I could not load the second or third bullet if I needed - but at this point it is much easier to load the 3p than a regular 24 - IF I do not patch. Another thing I do on quick second shots is to run the sabot/bullet combination on my tongue to add a little moister for lubrication - slides right down.
I know there are some TC barrels out there that are tighter than the norm and 3p's or 'crush rib's' are necessary even on a clean barrel.
Some additional information the original sabots on hornady's and barnes are equivelent to a MMP HPH-12. They are really tough to get down the barrel of most any TC product. The new Hornady 'low drag' sabot is a 3p in an effort to give the Hornady SST a competitive edge with the Shockwave products.
Sabots in the order of thickness
MMP HPH-12 and equivelents - good for a .504/.506 boresl (Older Knights and Whites)
such as Hornady and Barnes
MMP HPH-24 (.002" thinner than the 12)
Harvester regular short black - these are for the more standard barrels of the TC and the new GM barrels... .502/.503
Harvester regular long black
MMP HPH-3p-Ez load
Hornady 'low drag' .499/.500 bore diameter
TC 'super glide'
New Barnes sabot ( can not remember the name)
And the thinnest of the 50 cal sabots
Harvester 'crush rib'