If you have a rough opening. You might want to check for dirt or grit between the tang and the lock bar. It doesn't take much to make it drag.
As far as blade rub. I have found that every Chinook I have handled the blade rubs the liners. On the first model, I couldn't locate the problem as you couldn't easily disassemble the knife. However, on the II I have found the cause.
The pivot hole in the blade is just a bit too large for the pivot. This allows lateral play and makes it very easy for the blade to rub the liner. I have found this on the 6 I have disassembled.Another reason the blade rubs with the loose fitting pivot is that the grind on the blade sits low in the handle. If they took the grind higher or made it a flat grind as on the manix. No rubbing.
I have done two things to stop mine from rubbing. First, I took a few thousandths of the total length of the pivot. This allows me to tighten up the pivot more and reduce the lateral play a bit. I also relieved the liners a hair where the blade rubs. Another option, if you have the tools. Ream the pivot hole out to a larger pivot. This way you can make sure it is a tight fit with minimal play.
The blade rub is annoying, but doesn't impact the function of the knife. However, I have to admit, if I am paying that much for a folder I don't want to be annoyed by blade rub. I think Spyderco could do better on this knife.
A question to Sal - I have played with a lot Chinooks, I and II. I have played with several Manix and other Spyderco models. It might be purely my perception, but I have noticed more QC issues with the Chinook than I have any other Spydie. I am talking everything from uneven grinds, to the issue with the blade rub. I rarely see this on any other Spyderco. Is the Chinook that much more of a difficult design?
