Afternoon all.
I notice that some have the feeling that "full length sized" is full length sized, Period.
Not so.
Given that all manufacturing deals with production tolerences, the following can happen quite easily.
Let us say you have a rifle chamber which just happens to fall on the large side of the allowed tolerences.
This chamber IS NOT over sized, it is "within the manufacturing tolerences".
Now let us say we buy a set of dies, which are also made within the allowable tolerences and this "full length die" also happens to be on the upper (large) side of the allowed manufacturing tolerences.
You now have a situation where it is very likely the "once fired" brass from that rifle, sized (according to manufactures instructions) in that "full length die", will not chamber in a rifle which, while still within tolerences, happens to be on the other end of the allowed tolerence scale.
It happens!
Personaly as stated in other posts, I do not adjust my full length sizing die according to the manufactures instructions.
It only took me one time with a rifle having a chamber on the larger end of the tolerences and sizing according to directions with what might have been a die on the other end of tolerences, to find out this is a way to end up with very short brass life!!!!!!!!
I have for years, only adjusted my "full length dies" to the point where I have relyable chambering. If after firing those cases a time or two more, I find that the case is chambering a bit hard, I tweek the die down again just to the point where I again have relyable chambering.
After this process has been done a time or two, I will have arrived at a point where I am sizing my brass to the minimum which allows for positive and relyable chambering, while providing the longest possible brass life.
Once I have arrived at this point, I never need to change my sizer die setting again, UNLESS I change rifles, at which point the "new" chamber may require changes for best brass life.
The manufacturing tolerence thing is also why, one set of dies for 2 or more rifles with the same chamber/caliber designation, MAY(??) be less then ideal.
Keep em coming!
CDOC