I'd try a different powder, specifically - Black powder.
I learned years ago when sighting in a new rifle use Black Powder first to determine the accuracy potential, then switch to the substitutes to see if any of them are compatible with the gun.
Long story, but I almost got rid of a new gun because I first used the old Clean Shot powder in it. It shot terrible with every bullet style and load I tried and I cleaned it and stuck it back in the gun cabinet thinking I'd trade it off first chance I got. A few months later I was having accuracy problems with another rifle I knew was capable of great accuracy. It had shot well a time or two with the substitute powder, but suddenly just wouldn't shoot well anymore. I had some Goex in my range box and switched to it and the rifle started performing again! Then the light went on in my head and I remembered I had never tried real BP in the rifle I had set aside as junk. Dug it out, went to the range and shot 1" groups at 100 yards with it using Goex!!!!!!!!!
I've found that Pyrodex is usually as dependable as BP for accuracy, butmany ofsubs can be very erratic under some conditions. I've had rifle that shot really good groups one day with APP, then terrible groups a day or two later with the same load. I haven't used enough T-7 to have confidence in it yet, but so far it seemsto beconsistent and gives decent accuracy.
For now, my hunting load is either BP or Pyrodex in all my rifles. Perhaps someday I'll find a dependable substitute, but for now I'd rather spend an extra few minutes cleaning the rifle than take a chance on poor accuracy when I'm hunting.