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Bushing Neck Die

Posted: Sun Feb 27, 2011 7:03 pm
by Dangermouse
Not wanting to ambush the "bushing bump die" post

After frustrations with the Lee dies I spent out last week on a set of Redding Competition Bushing Neck Dies.
http://www.sinclairintl.com/.aspx/sid=7 ... NECK_DIE_S

Paying way too much attention to the bullet seater I did not realise that the De-capping / Neck sizer die uses Bushes, and yet again I find that I am going to have to order something else which is missing from the item that I wanted.

Reading up on the bushings I understand that I have to make a round up first and then measure the neck +.001 to get the bushing that I need, so perhaps I had to wait for the bullet seater to arrive first.
This die has the ability to determine how much of the neck gets sized. As this is not something that I have had to consider before can anyone help with what I need to consider in making this decision?

DM

Re: Bushing Neck Die

Posted: Sun Feb 27, 2011 7:51 pm
by ovenpaa
Dangermouse wrote:This die has the ability to determine how much of the neck gets sized. As this is not something that I have had to consider before can anyone help with what I need to consider in making this decision?
You need the one I ordered by mistake from SincInt, I wanted to buy a size down when I was experimenting with neck sizing but ended up getting the one I already used. :(

So I have a couple of neck sized cased that I cannot use with a bush I cannot use.

So do you want a bush? I can confirm the size in the morning but whatever it is, it is the same as the one I have used for the last few years. It is a Titanium Nitrided one so a nice shiny gold colour.

Re: Bushing Neck Die

Posted: Mon Feb 28, 2011 9:59 am
by rox
Dangermouse wrote:I understand that I have to make a round up first and then measure the neck +.001 to get the bushing that I need
You’d better size to -0.001” (1 thou under), otherwise the bullets will fall out.

Redding currently recommend 1 thou tension as optimum compared to their initial 2 thou suggestion, but in some situations 2 thou may still be a good idea (e.g. for magazine use, or less cosseted applications).
Dangermouse wrote:This die has the ability to determine how much of the neck gets sized. As this is not something that I have had to consider before can anyone help with what I need to consider in making this decision?
The idea of sizing only part of the neck is as follows:

Some people neck size because a fire-formed case can (in theory) place the bullet more concentrically with the bore centre-line, improving accuracy. When neck-sizing, only the part of the neck that is in contact with the bullet actually needs to be sized, so leaving the rest of the neck fire-formed can further improve the concentricity of the round in the chamber. In the image below, the green line indicates the part of the neck that has been sized (about one-third of the neck), while the remaining two-thirds are left fire-formed (the red area). Naturally, the amount of neck to be sized depends on your bullet profile and seating depth (and must allow for any variation in seating depth). In this example it would probably be best to size nearer to 50% of the neck to allow for such variations.
neck-size.png
In some circles it is currently more fashionable to full-length size, rather than neck size, on the basis that full-length sizing produces a more consistent round, particularly with less than perfectly concentric chambers (which all are, to some degree). The choice depends on your application and your chamber, so appropriate testing is the only way to choose. Neck sizing with dry lube can be considerably less hassle if you load in any quantity. Personally I use neck or FL without any observable difference in performance, but since I shoot without optics or a rest, a half to three-quarter minute group at 1000 is the best I can hope for – any difference due to sizing method is likely to be invisible to me.

Some claim that the coated Redding bushings can be run without lube – others say to always lube regardless. Durability shouldn’t be a concern, unless you plan to load, say, 100k rounds plus.

..

Re: Bushing Neck Die

Posted: Mon Feb 28, 2011 11:30 am
by Dangermouse
Rox

Thanks for taking the time to write that great answer which answers as much as I need to know. I look forward to playing with it when they finally clear customs etc,

Dave, pm sent,

DM

Re: Bushing Neck Die

Posted: Mon Feb 28, 2011 7:05 pm
by TobyH
Yes thanks Rox, it's always good to see a straightforward explanation in laymans terms!