Frank, as you might know, I have been in the machine shop business for 50 years and have machined parts that did require tolerances in the .0005 range. What most “lay persons” do not understand is when dealing in sizes below that level of accuracy, you have to be in a controlled environment where temperatures are regulated to the term “room temperature”, or in specific cases to an engineered specification.
if You read the link furnished in post #105, you probably noticed that remark about recoil lug squareness in conjunction with the receiver threads and receiver face. The author stated that .0001 out of true square would equate to a much larger .100 number if triangulated out to 100 yards.
It was implied that this would cause the rifle to automatically be locked into a .100 capability, or “spread” as he called it. That statement is simply asinine. Just because a barrel is pointed out of square with the receiver does not equate to the rifle’s ability to agg. Granted, you do want things as square as possible, (I say “as possible” because the author was once again tossing out that .0001 tolerance), but having everything machined perfect still does not guarantee sub .200 performance unless the bullet/barrel/powder/tune combination is equal to the task.
Any competitive Benchrest Shooter can attest to that.
You are probably like me in that you do take many of these discussions with a grain of salt. It is only when they cross over into the unrealistic realm, usually in an attempt to sell a product to a gullible clientele, will I get involved.