Kerndog.. Welcome to the forum.
You did not mention what kind of projectiles you tried or the kind of powder you are using. When I have no idea what a rifle will shoot, and it has a 1-28 twist I usually start with 85 grains of 2f powder, whether it is Pyrodex, Triple Se7en, of Goex. I shoot loose powder. Then on that charge,I load a 240 grain T/C Cheap Shot or a 240 grain T/C Mag Express XTP. Normally those will shoot well out of most rifles.
If those do not work then I look at the 300 grain XTP and keep the same powder charge. Again, I start at 85 grains and work the powder charge up from there. With your rifle I would keep the loads at 100 grains of loose powder or less.
When sabots do not work then I look at maxiball or 245 grain Powerbelts. I do not have your rifle. I am just telling you where I would look. Whether it will work for you I have no idea.
"Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, a total wreck, screaming Yahoo, with a big smile on your face."