RE: Where to go from here?
Try loose 777 with 250 gr TC Shockwaves. I would use Shockwaves over Hornadity SSTs because they use a thinner sabot and usualy load easier in TC guns. Use from 100 to 120 grs of loose 777. If you prefere Pyrodex try the loose powder so you can go up 5 grs at a time until you find what your rifle likes ( you can use up to 150 grs. of loose Pyrodex but not more than 120 to 125 grs of loose 777. Most all Omegas and Encores like 250 Shockwaves.
If you decide to use 777 it would be a good idea to buy some Winchester 777- 209 primers. With these primers and 777 you will have a cleaner, and more powerful load. Most use 2F - 777 but I prefere 3F. Using 120 grs of 777 and a 250 gr Shockwave I get a5/8 inch group at 50 yds. and around 1 1/2 inch at 100 yds. That is with an Omega but Encore's have a sililar barrel. All guns are different but this should give you much better results than you have now.