Redding sizing bushing - seeking size selection guidance

[B!ngo]

Hello,
I am new to using the Redding Type S match dies. The sizing die requires the selection of a bushing to 'fine-tune' the case sizing. I've read a lot about it on line but I must admit that I am still confused about how to choose the size/sizes of bushing for my specific need.
Some say that you base the size on the case size of the commercial brass you have been using and then add a small amount to the rim diameter to choose the bushing.
It seems to me that basing the bushing size on a fire-formed cartridge/neck size would be the way to go. Of course this breaks down if you are reloading for multiple guns in the same caliber. Would you have to keep the reloads separate, choosing the bushing based off of the fire-formed cases of each firearm?
Is there something simple and obvious that I am missing here? The bushings are pricey ($25.00) so buying 'one of each' is a non-starter.
Any info would be appreciated.
Thanks,
B

 

[243winxb]

Measure loaded rounds neck diameter. Find the smallest one of the lot. Buy a bushing .002" smaller. You will end up buying about 3 bushings. If loading for an auto, buy a bushing .003" smaller.

 

[USSR]

Some say that you base the size on the case size of the commercial brass you have been using and then add a small amount to the rim diameter to choose the bushing.
It seems to me that basing the bushing size on a fire-formed cartridge/neck size would be the way to go.

Actually, you base it on both. While in most cases (no pun intended) you want to use a bushing .002" less than the neck OD of a loaded round using whatever brass you intend to use, the fire-formed neck size needs to be taken into consideration. Why? Because if the fire-formed neck size is more than .005" than whatever size you want to end up at, the proper bushing will resize an additional .001" more than it's stated size. That's why many of us use an intermediate size bushing prior to using the proper size bushing. Hope that helps.

Don

 

[Walkalong]

You will end up buying about 3 bushings

Amen brother.

http://www.thehighroad.org/attachment.php?attachmentid=181779&d=1364057403