Buying dies. Mystery procedure?

[sunray]

"...dies would have to be matched to my rifle..." His eyes brown?
Go buy a copy of The ABC's of Reloading. Then look into an RCBS Beginner's Kit. (Not from the guy you first talked to though.) Gives you everything you need less dies and shell holder.

 

[Ganderite]

There is an element of truth. The finishing reamer will wear and chambers get smaller (tighter.) The last chamber cut will be a bit tighter than the first chamber that was cut. Both both should be within the SAAMI spec.

I have multiple guns in some calibers, and muy loading log book notes which is the tightest. When sizing, I size so brass just barely fits that chamber and I know it will work in all the others.

I have 27 rifles in 308 and the BLR is noticably tighter than all the others.

I have 5 pistols in 45 ACP. 4 of them seem about the same (digest anything) and my Star is much tighter. If I don't clean it factory ammo has some resistance. When adjusting the taper crimp, I use the Star as the set up guage.

 

[acrashb]

i understand your point
[...]
and rotating it further at first makes no sense as it would make the whole shell plate of a progressive tilt on one side

His point was about friction - irrelevant, it's about brittle carbide maybe cracking.

Regarding tilting the progressive, that's why the sizing die is placed where it is.

 

[TwoTone]

The reason that you preload is to make up for the extra resistance encountered when actually sizing a case.On a press that flexes under load or that has some slop in the linkages,you might not be able to fully size the case without some preload.

stubblejumper, thank god somebody finally said it! I was really hoping somebody would explain that. Even in a robust press, without preload the case may not go all the way into the die.

The same problem comes in to play when supposedly setting the dies to 'just size enough' to fit the chamber. The only way to accomplish consistant results trying to do that is to have a positive stop for the ram at the end of the press stroke, otherwise the press can flex different amounts with each case and you end up with different degrees of resizing.

Redding makes a set of shell holders with increasing rim thicknesses for just this reason.

 

[Dogleg]

Hmmm. A little prussian blue and we're off to the races then?

Or a match.