I'm no gunsmith, obviously, but I can't understand how this could be attributed to the barrel.

Isn't the surface of the barrel where the scope is mounted parallel to the bore? And, isn't that the case with many similarly designed guns on the market? If so, it would not seem that the barrel could possibly be to blame.

Are you saying that the bores of T/C barrels are pointing downward in relation to the part of the barrel where the scope is mounted?

I'm just not aware of anything else that could cause this "known, frequent" problem. If this is a known problem, enlighten me to what is wrong with T/C barrels. Thanks.