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 of the rifle for which you are reloading 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? This isn't currently an issue for me (I have one 308 - a Tikka Sporter) but will be next year when I would like to acquire a 308 semi-auto.
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

[CSACANNONEER]

Are you neck turning? Brass thickness will vary from lot to lot (I won't even get into it not be consistent thickness all the way around) so, you will need to know the thickness of your brass at the case mouth, figure out just how much neck tension you want (again this will vary from lot to lot and even vary from firing to firing unless you anneal every time) and then do a little basic math to figure out what size bushingS you want.

[B!ngo]

I was not planning on doing neck-turning. I don't have the bit and bobs to do it and my needs and skills don't require it. For now at least.
I assume that without neck-turning there are fewer 'knowns' (or more variance). I'm not sure how to deal with that.
B

[J-cat]

You need to pick the bushing that's appropriate for the brass you plan on using. Obviously Winchester will have a smaller loaded neck diameter than Lake City. Measure your loaded round neck diameter and pick a bushing .002-.003" smaller.

[CSACANNONEER]

Neck turning would help make different batches of brass have more consistent neck thicknesses and require you to get fewer bushingS. Personally, unless you are a top shooter and anal reloader, I suggest just using a FL die and/or a Lee neck sizing die for now. You will have to FL size every so often anyway.

[D.carden]

The bushings are only for the neck portion of the die. I load .223 for an AR15 and use a .242 bushing in a full length Redding Sizing Die. The LC brass that i use has a loaded neck diameter of .246, thus using the .242 bushing at the sizing process gives me .004 of neck tension (squeezing the bullet tension). I also eliminated the expander button in the decapping pin. Bolt guns might not need that much tension.

[Fjold]

The bushings are only for the neck portion of the die. I load .223 for an AR15 and use a .242 bushing in a full length Redding Sizing Die. The LC brass that i use has a loaded neck diameter of .246, thus using the .242 bushing at the sizing process gives me .004 of neck tension (squeezing the bullet tension). I also eliminated the expander button in the decapping pin. Bolt guns might not need that much tension.

+1, Get rid of the expander button on the decapping die. The bushing die doesn't work if it sizes it to get you a specific neck diameter and then you drag the oversized expander button back through the sized neck.

I have a universal decapping die (doesn't touch the case necks) that I use for all my target loads.

[B!ngo]

Thanks. I was considering getting a FL die as well, since it seems to be needed now and then. But in the Redding case, don't the FL dies also require the bushing? At least the S-model does, no?
B

[JMP]

From yesterday:

http://www.calguns.net/calgunforum/showthread.php?t=979408

Hence, I won't repost, except I will emphasize CSA's "bushings".

[B!ngo]

Guess I missed it.
I still find it confusing (except the part where I might have been better off with Lee dies).
It you're going to base the measurement off of a piece of commercial brass, then why do they make so many die sizes? The could just pick a piece of Federal Match, construct the bushing from that and done. In fact, why ship a separate bushing at all?
So Redding is ensuring that the reloader can and wants a significant degree of variance and provides this bushing choice option to do so. Confusing.
B

[Fjold]

Guess I missed it.
I still find it confusing (except the part where I might have been better off with Lee dies).
It you're going to base the measurement off of a piece of commercial brass, then why do they make so many die sizes? The could just pick a piece of Federal Match, construct the bushing from that and done. In fact, why ship a separate bushing at all?
So Redding is ensuring that the reloader can and wants a significant degree of variance and provides this bushing choice option to do so. Confusing.
B

Because Redding makes these dies for precision reloaders. They are made for idiots who get custom chambers cut for specific dimensions.

I have a 22.250 with an undersized chamber. I had the chamber cut to minimum SAAMI spec and with a .250" diameter neck. I use Norma brass and turn the necks so that when they are loaded with a 69 grain SMK the loaded diameter is .248. I use a .245" bushing which after spring back gives me a .246" diameter case. This gives me a .248 diameter loaded cartridge with .002" of neck tension.

My 6.5x284 has a .298 neck diameter and the stock Lapua brass loaded with the 142 grain SMK gives me .2955. I use a .292" bushing for that load.

[J-cat]

Guess I missed it.
I still find it confusing (except the part where I might have been better off with Lee dies).
It you're going to base the measurement off of a piece of commercial brass, then why do they make so many die sizes? The could just pick a piece of Federal Match, construct the bushing from that and done. In fact, why ship a separate bushing at all?

They make different sizes because brass thickness varies between brands. The whole point is to give you adequate neck tension without overworking the brass. A standard die is designed to provide adequate neck tension with all brands of brass. It accomplishes this by sizing the neck .010" more than it should and then opening it back up. This overworks the thinnest of necks, and downright abuses the thick ones. Conversely, a bushing tailored to a specific neck thickness sizes the brass only .004". The brass springs back .001" on its own and you end up with .003" tension. If you want less, use a .003" smaller bushing for .002" tension. Some people use bushings the same size as their neck to allow them to soft seat the bullet into the lands upon chambering.

The benefit is you control neck tension and the cases last longer.

[JMP]

Guess I missed it.
I still find it confusing (except the part where I might have been better off with Lee dies).
It you're going to base the measurement off of a piece of commercial brass, then why do they make so many die sizes? The could just pick a piece of Federal Match, construct the bushing from that and done. In fact, why ship a separate bushing at all?
So Redding is ensuring that the reloader can and wants a significant degree of variance and provides this bushing choice option to do so. Confusing.
B

Get a ball micrometer, measure the neck thickness of a Lapua case, then a Winchester case. You will see why there are different sizes. If you want to use all the same size neck sizing, there is no need for the type S.