Well my wife and I both have 50 caliber Encores. I have 4 freinds that have Encores. They all shoot great. Mine will shoot anything I put in it. My one friends is a little pickier, but not very.
As far as hard loading, that is not due to the Encore in my opinion. That is due to the nature of the sabots that everyone chooses to shoot. Have you ever tried to load a sabot in a sidelock, they are tough in them too. If sabots are loading hard, try Powerbelts, they slide down like butter. 45 Cal sabots load harder than 44 cal sabots. Barnes or Red Hot bullets load harder than either. Maxi-balls will load pretty easy.
Some guns will not shoot the 44 cal sabots accurately so you must look at a harder to load sabot option, or something like the Powerbelts. Bottom line is that there is not an industry standard for the barrel dimensions of a black powder barrel. They are will vary and that is just the way it is.
Someone is this forum recently sent a barrel back to T/C because it was not grouping and T/C said it probably had a bulge in the barrel (it might have been you, I cannot remember). I did not buy that when I read it, sounded more like sabot failure to me. Sabots are great and I shoot them myself but they require more experimentation since their are more variables with how they work than in the old days of just stufing a Maxi-ball down the barrel. Aint technology great, sometimes!
You also do not say how much powder you are using. When you start getting up there over 100 grs., the type of sabot becomes more important because of the pressure. Guess what, the higher pressure sabots are much harder to load and they are more prone to fail and lead to poor accuracy. I have never been a fan of shooting the big powder loads because of the other problems it creates. If you look at a velocity chart, the gain is very little for the amount of powder stuffed in the barrel when you get up into the magnum loads.
Good luck with your Encore, I have no doubt it can be made to shoot well with bullets in the 240 to 300 gr. range.