I did not read the article but I'll give my $.02 anyways . I think the most important thing in this is the term "CAM" over . A press that cams over is just insuring your die and shell holder make hard contact . The camming action is forcing hard contact between the two . You can adjust any die to not cam over in a cam over press and still make hard or light contact . You just screw the die down more . It will then be up to you and what you feel to insure you size the case properly .
Now my understanding and experience of why you want can over or hard contact between die and shell holder . Some presses have more flex/deflection in the linkage or press it self then others that results in inconsistent "case head space" ( length from head to datum point on the shoulder)
Case in point is the Hornady LnL classic single stage press . IMHO this press has a lot of flex/deflection compared to others . Depending on the size and how work hardened a case is you can get as much as a .006 swing in "case head space" if the die and shell holder do not make hard contact .
These pictures show what I mean . This is two pictures showing the Hornady single stage press and how much deflection it can have when sizing a 308 case .
First pic is the ram fully up and the die screwed down to just kiss the shell holder .
This second pic shows how much stretch/flex/deflection the press has when sizing the 308 case with the die locked in place as shown above .
That shows how one can get very inconsistently sized cases . It also can explain how if you have a chamber that needs you to FL size a case and you set the die to touch the shell holder but when you size the case it does not bump the shoulders back enough . It is do to the press deflection .
Now when sizing for a specific chamber size and or just bumping the shoulder back .002 or so . Many don't even need the die and shell holder to touch . This is true in my case and resulted in very inconsistent "case head space" do to how much my press would deflect/stretch .
What I ended up doing was using a feeler gauge under the case head between the head and shell holder to raise the case up a tad to bump the shoulders a little more when needed .
To clarify I did not need to do this on every case . Most would be sized to what I wanted but there were some that fought the resizing . Those cases would not have there shoulders bumped back as much as the others . On those cases I'd lift them up in the shell holder and resize them again resulting in the shoulders being bumped back the extra amount the feeler gauge raised them .
I used this method for quite a while which resulted in me needing to measure every single case after sizing . It was very time consuming to get all my cases sized perfectly or shoulders bumped .002 .
Then I was introduced to the most beautiful product . That is the Redding competition shell holders
. It was all peaches and cream after that . These shell holders are designed to remove all press deflection/flex while still controlling the size of your "case head space" . Each shell holder ( set of 5) is .002 taller then the last resulting in you being able to size a case .010 longer while still making hard contact then you can with a standard shell holder .
Since then I now can size a few cases to get the right shell holder . Once I have the right one for the sized case I want . I no longer need to measure every case to insure it was bumped back correctly . They all come out VERY consistent . The time I save and the consistency I get makes the Redding competition shell holders well worth the cost .
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They also help when loading for different rifles with different chamber sizes . Instead of adjusting the die for each rifle . You just swap out the shell holder .
Redding through Midway USA said:
The Redding Competition Shellholder Kit #1 consists of five shellholders in varying heights with increments of .002". Allows you to increase or decrease the case to chamber headspace without adjusting the dies.
AS for carbide dies . They are almost always for non-shouldered cases which a little press deflection is not going to effect the end result .