Reamer designing?

[Changeling]

It would probably be best if I describe what I want to do and let the experts give there opinion,6BR Norma).
1. Irregardless of shoulder angle I want to have a chamber,6BR) capable of soft seating bullets from 55 to 107 + if possible. I understand soft, medium, hard seating and the impossibility of having an exact combination of all of the above.
2. I know and understand that there are differences,slight) in the diameter of the various bullets and the bore of various barrel makers which makes this "Not" an exact science.
However there must be some happy medium that corresponds to neck length, diameter and tension that can be utilized in this type of equation. If I missed something please let me know so we can discuss it.
Changeling

 

[mikecr]

Pretty tall order for that bullet range. My more or less standard chamber has .060 freebore. I believe this will get you close for the lighter bullets. But 105Lapua's are seated deep,boat tail below neck-shoulder).
My neck was to be .269, but the reamer must have been worn as my finished neck is .2675. I turn anyway, so it's no big deal for me.
With a 6Dasher reamer order, I set freebore @.090, & coaxial @.2431,very tight). The neck in this was set to .2670 for .0115 turned neck thickness. All other aspects of this chamber were left 6Dasher Std. I use a tight coaxial throat because my loaded ammo generally indicates TIR @ the ogive under .0005. And when I close the bolt, I know it's under .0001,or I couldn't have closed the bolt). This increases starting and overall pressure w/resp to listed or predicted loads though. Quicker seal.

Tension you set when tuning the load. I use wilson bushing hand dies and machine spacers to adjust the length of neck size. My bushing will only bring it down .001 under bullet diameter and springback leaves it at .0005 under. But I start with as little tension as needed and work up. The less sizing here the less runout you end up with,assuming your chamber is straight).

Good luck

 

[Changeling]

Mikecr thank you for replying. I understand what you are saying but I am not interested in turning case necks at this point.
I want to set up the chamber to soft seat with the widest bullet range possible without encroaching on the powder supply. I suppose this means that I will have to decide on which end of the scale I want to soft seat for the best precision.
I would rather have the heaver bullets soft seating with full powder supply capability and have the lighter bullets make the jump to the rifling as/if necessary. Does this sense the way I say it to you?
So my dilemma is whether to use a standard 6BR Norma case or go to the Dasher! With the Dasher I would have the slightly higher case capacity that might make up for lighter bullets having an increased free bore. With the standard 6BR Norma I would have the advantage of the longer neck.
This particular barrel is for precision long range varmint and accuracy matches in a private club, if that is of any help.
Changeling