I feel your pain and you are at much the same point I was with the .45, though your rifle is shooting better. Suggest shouting at TC one more time - tell them you want a non-washboard barrel. For the money paid, a person should be able to count on getting a properly rifled barrel.

Have you tried an overpowder wad with the conicals? Using a fairly thick overpowder wad might help a bit. Track of the Wolf has good prices, search for WAD-510-A . Reasonably inexpensive experiment in any case.

Is your barrel stainless?