Mark Gordan method for finding depth to lands??

[Winny94]

I really like this method for finding distance to lands as it is extremely quick and consistent, but im running it through my mind and logically, there is a literal and figurative gap for me.

Please correct/educate me, but wont having the case rim under the extractor pull case back a few thou vs the measure you find here? Assuming you are using well formed brass, wouldnt need to add whatever shoulder bump you size to? For example; lets say you find you CBTO with this method is 1.810. If I bump my shoulder back .002 from a well formed fired piece of brass, would you not need to use 1.812 as your CBTO at lands?

 

[spife7980]

You don’t factor that stuff in if you’re using the barrel only method.

It’s not measuring the bolt face to lands, it’s measuring chamber shoulder to lands.

 

[MakeSawdust]

I use this method to track throat erosion and to make sure that I am not touching the lands. I do not want to touch the lands because I do not want to pull a bullet when unloading a loaded round.

To understand how much the distance from the lands matters in keeping the gun in tune, go watch Erik Cortina. Find the node and shoot the gun. I have chased the lands on several barrels AFTER doing it the way Erik describes (before he put out the videos). I did this because the internet said it was "the way."

I have gone back to doing it the way Erik does it. My life has become a lot easier, and my loads stay in tune better/longer. Do not make this stuff too complicated. It is simple. I know some people's minds want things to be just so. I am that way. I can tell you after wasting a great deal of time, it will not change how the gun shoots.

Also, spife is correct. Reference from the shoulder to the ogive for a measurement that is "just right".

 

[SporterII]

Just right meaning a repeatable method.