I have been relaoding for many years, but I am steping up my game a little.

I have aquired Redding competition dies for three calibers. .260rem, 6mm ack imp, and .284 win. The 6mm has a .266 neck.

So, my question is, is there a formula for determining the prober bushing size to start with?

Thanks for the help,

Chris

Bullet dia + (2x neck thickness) - .002 will get you close.

Alt, seat a bullet, measure the neck diameter, get bushing that's .002 smaller than that.

That should get you started/close. You may want to also pick up bushings that are .003 and .004 smaller, so you'll be better able to tune the neck tension.

quote:

So, my question is, is there a formula for determining the prober bushing size to start with?

Sort of as tailgunner shows BUT

Cases vary in thickness within a given manufacturer's lot and from lot to lot over time. Cases vary even more from brand to brand. If for some reason you decide to turn the necks you may need a different bushing.

For example - for 6mm Remington cases
Remington brand necks are thick and tapered so much they do not work well with the Lee collet neck die.
The Winchester brand cases are thinner but do not have the taper that you will find in the Remingtons.
As a result you may need 2 or 3 bushings for some rounds.

On another point - you might like the Redding neck bushing die for the .308 winchester.
Its ID is large enough and it is short enough to be used to for about 30 different rounds.

It will work for .30-30 length rounds up as long as the case will fit inside the die. It appears this die will work for rounds up to .338 caliber.

.358s will not work but Wilson makes bushings for rounds up to .338. The fat magnum, short magnum, .284 Win and it wildcats will not work.
Neither will the fat military rounds like the 7.62X54R Rooski, the 7.5X54 French MAS and the 7.5X55 Schmidt-Rubin.
I do not like the Redding bushings. They do not have a very large radius at the entrance to the bushing bore. The Reddings are ok if you do not mind spinning the bushing in a lathe to stone out the radius.
You will learn all of this given time.

Thanks for the help guys.

Will other/better bushings work in the reding dies?

Riverman,
The Wilson bushing are identical in external dimensions to the Redding bushings.
I have no idea what the dimensions of RCBS bushings are. Forster bushings are definitely not a fit in Redding dies.

To be clear, Redding bushings are of very high quality. Only the sharper edge raidus is a bummer if you are sizing a case about .010. If you are sizing a case only .005 or so, you might be happy with the Reddings. The radius can be polished larger if you have access to a lathe or even a drill motor with a 1/2" chuck.

Where you will really enjoy the bushing dies is when they are used for neck sizing. Sizing only a minimum amount to hold the bullet requires no case lube and very little force. If you try a set of the Wilson arbor press dies you will be amazed at the simplicity and precision. They are pretty much the standard tools used at bench rest matches.

Edit update
I just opened another Redding die. It has a nice radius that is the equivalent of the Wilson die. This is good. It is much easier for me to read the numbers on a Redding bushing.