View Full Version : necking dies

02-07-2009, 10:00 AM
I've looked around for necking dies asked etc but can't seem to come across any for the 303 british and 8 mm mauser.:???: it's hard on the brass for the 303.

02-08-2009, 02:10 AM
You would probably just as fast to order one from one of the manufacturers.

02-08-2009, 04:31 PM
If you mean neck sizing dies, what brand(s) are you interested in? Midway has a bunch of different ones in stock(mostly), conventional, collet, and bushing for both cartridges.

If you mean case forming dies for progressive neck downs, you usually have to order them direct from RCBS.

02-08-2009, 05:14 PM
was on Midway this morning I got a RCBS rock Chucker. I'll probably call RCBS tomorrow Thanks for the input guys you helped.

02-19-2009, 12:38 AM
The tech at RCBS wrote:
The part number for the 303 British is 15430 and the 8x57 (8mm Mauser) is 15930. Both list for $34.95 each. Are you needing a neck expander die or neck expander plug for cast bullets or a decap unit for the size die?

Dave says,

So I guess I need the decap unit included. Now I was wanting to try cast also so do I need the neck expander die or the neck expander plug? along with just being able to neck for manufactured tips.

02-19-2009, 02:12 AM
The expander plug (or ball) is part of the decapping stem on a sizing die. Sometimes it is a part that comes screwed onto the end of the stem and holds a replacable decapping pin, and sometimes it is machined as part of the stem. You don't buy it separately, though the stems are accidently broken occasionally and need to be replaced. Small Base, Full Length, and conventional Neck Sizing dies all have expander plugs on them. The neck portion of the die reduces the diameter of the neck and the expander plug expands it to the proper diameter as the case is pulled out of the die by the ram of the loading press. Collet Neck Sizers do not need them as the neck is resized by means of a collet closing on a mandrel of specific diameter. Bushing dies don't need them either as the neck is sized in an interchangable bushing for an exact fit in a tight chamber like a match rifle. You might want to do a little more research into the three different kinds of neck sizers and their strengths/weaknesses to decide which is best for your needs. Conventional or collet will probably meet your needs unless you have a custom chamber. Collet dies are least expensive, conventional neck sizers have been working well for a century, bushing dies are very costly though the most versatile and if you can afford them are often a smart investment for a competetive or long range varmint shooter.

An expander die is what you need to prepare rifle cases to load larger diameter cast bullets in them. They are either caliber (not case) specific, like the Lyman "M" dies, or the universal sort that Lee sells. Handgun die sets come with them, rifle sets do not. They are also called "belling" or "flaring" dies.

It is a lot less confusing for everyone if a beginning loader takes the time to learn and use accepted terms for components and tools. Questions are much clearer and answers make more sense that way. :)

A "tip" or jag is something that is screwed onto the end of a cleaning rod. I assume what you meant was "bullets". You don't need a special expander to load jacketed bullets in rifle cases, but it does help seating ease to chamfer the inside of the necks with a chamfer/deburring tool first. This only needs to be done once initially, then after each trimming the case must be both chamferred and deburred (the chips and sharp edge removed from the outside of the neck).

02-20-2009, 12:25 AM
This might help your case, no pun intended.

I use what is called by RCBS as their FL X-Sizer die on my 308, 7mm, & 25-06. What is does is once you full length size your brass with the die you will never have to resize the case below the shoulder again for the life of the brass. All you need to do is neck size after every firing. Once the brass becomes what is called "fire formed" to your rifles chamber the brass should never grow again unless you are loading to the max pressure of a particular load. Most dies don't give you this option. Basically the die allows you to just neck size if thats all you need. Typically other die manufacturers will include a separate die for this option. Hope this clears the picture for you a little more.


02-20-2009, 12:28 AM
thank you this is giving me more home work but I'll learn from it and that is the whole purpose.

When I stop learning please bury me.

03-02-2009, 11:56 PM
Have gone to lee collet neck sizing dies for most of my non milsurp rifles, and have no complaints. Saves time, saves lube process, and it just plain works.
For years I just neck sized if you wish to call it that by not running all the way up in full length sizing dies. It worked, but not as well for me as the present method.