Agree'd..
Make the loaded cartridge fit in the magazine and move freely so it cycles through the action to chamber.
For the beginning reloader, I suggest that the OAL, is really a measurement from the case base to the ogive where it would contact the lands of the bore. Learn how to do this. (Bullet comparator) Backing off .005-.009" from the lands is a good place to start and will likely be quite close to the OAL (sammi) spec in the book.
That said, the barns 168 tsx is not a lead exposed bullet so measured bullet length should be quite consistent. (measure a bunch of the bullets and come up with an average length out of one lot/box.)
Your loaded cartridges should not vary more than +-.003". If you're loading for hunting purposes and not long range sniping, then you'll never notice +-.005" difference having an effect on accuracy.
-Steve