Redding S-type neck die question

[North Star]

I've just been stroking my new Redding S-type neck sizing die (.308), but I have a question regarding the expander ball. I thought the idea of the sizing die was to close up the neck to provide consistent neck tension, so why would you use an expander ball as well? The kit came with the expander ball installed which measures .306" diameter, and this also squeezes the collet that holds the decapping pin. There is another collet clamping sleeve supplied and this is small enough to pass through the neck of a re-sized case. Strangely, there is no mention of this in the instructions and no diagrams on how to use it, just some written instructions? Do I use the expander ball or not? I am reloading for target rifle shooting using Lapua Palma cases and 155g Lapua Scenar's.

[rox]

thought the idea of the sizing die was to close up the neck to provide consistent neck tension, so why would you use an expander ball as well?

You're right. It would be ludicrous to use an expander ball. Remove it immediately.

..

[Laurie]

The 'S' die is meant to be used in either of two ways:

1) neck-turned cases, or high grade out of the box brass whose necks have been measured and if necessary batched. (ie consistent neck thickness). Without the expander and the alternative collet decapping pin holder in position to retain the pin.

2) Other cases - with the expander ball in use. The bushing size should be chosen so that the ball barely kisses the insides of the neck. If the neck is lubed as it should be, it is hard to actually feel the case pass over the ball on a good bench press there is so little work being done.

The reason for this is that if there are any thickness variations in the brass, either between cases (one being say 13 thou', another 14) or around the neck of an individual case, the bushing alone gives undesirable sub-optimal results. Where neck thickness varies between cases, case A gets more or less neck tension applied than case B by the bushing. Where there is variable thickness around the neck, inconsistencies are pushed to the inside wall (ie no longer a perfect circle) and the bullet has to swage the neck walls out again on seating, which generally degrades consistency.

Redding says it on its online die description as:

The decapping rod is supplied with a standard size button. This is especially useful for reloaders who are using commercial brass as is.

A decapping pin retainer is also supplied with most Type S - Bushing Dies except 17 and 20 Cal. This enables neck sizing without the use of the size button for those who sort and/or turn case necks for uniformity.

[rox]

2) Other cases - with the expander ball in use. The bushing size should be chosen so that the ball barely kisses the insides of the neck. If the neck is lubed as it should be, it is hard to actually feel the case pass over the ball on a good bench press there is so little work being done.

Don't you think that the results with un-turned necks using no expander with reasonable quality brass are still better much than the adverse effect on straightness/runout that the ball induces?

[Laurie]

2) Other cases - with the expander ball in use. The bushing size should be chosen so that the ball barely kisses the insides of the neck. If the neck is lubed as it should be, it is hard to actually feel the case pass over the ball on a good bench press there is so little work being done.

Don't you think that the results with un-turned necks using no expander with reasonable quality brass are still better much than the adverse effect on straightness/runout that the ball induces?

No! Not if the die is set up correctly with a bushing that only just allows the case with the thinnest neck wall to be 'kissed' by the expander. A lot of the problems created by a conventional die arise from the massive amount of over-sizing involved followed by an almost equally large amount of expansion.

I once added up all the brass movement in the firing / sizing / expansion cycle of a 308 Lapua case in a well made factory rifle (FN Special Police Rifle) and it came to IIRC 44 thou' with a standard FL die. Some of that is unavoidable irrespective of die type thanks to the large case-neck to chamber clearance hence neck expansion on firing in a non-custom chamber, but even so a correctly set up 'S' roughly halves the amount of movement.

As I say, the trick is to use a bushing that requires hardly any expansion. I can't remember if the standard Redding steel expander is screw on or floating, but Redding offers an optional extra carbide expander that definitely does float. I bought that alongside my 308 Win 'S' die (the only one of the type I have) and the results are very good indeed with decent out of the box (Norma, ex NRA RWS, Lapua) cases, nil to very low TIR values.

Of press mounted bushing dies, I prefer the Forster Bushing-Bump type if loading for one rifle only so FL size isn't needed. In a minimum SAAMI 308 chamber in a custom F/TR rifle running 155s at 3,050 fps, I've never had to FL size in several barrels on this rifle other than for the first use in a new barrel / chamber - it appears to be the shoulder movement that causes hard chambering extraction with neck sizing only and the [shoulder] 'Bump' bit of the Forster design deals with that. This die comes without an expander ball, although one can be bought as an extra as it assumes use of turned brass. Even with turned brass, I marginally over-size (0.001" smaller bushing) and then separately expand with a Sinclair expander die body and appropriate E size mandrel with the inside neck lubed. This is a step too much work for most people, but there is some evidence it gives more consistent neck tension than neck-sizing alone.

The mandrel die option is an alternative to anyone who wants an expander but doesn't like the conventional variety on the decap rod. I use Sinclair E-types (sold for the pre turning expand step) and like the amount of tension I get in half a dozen calibres from 224 to 308, but you can now buy custom made ones from PGS Precision Engineering in small mandrel diameter gradations to get exactly whatever tension is desired.

http://www.targetshooter.co.uk/?p=2823

A write-up by FB-UK member 'The Gun Pimp'.

[North Star]

I managed to get the die working well and I'm already impressed with the consistency. I did have to polish down the decapping pin as the palma cases have a 1.5mm (0.056") flash hole and the supplied pin is 0.060"! I did see the information on the Redding website that Laurie mentioned, but at first I thought it was odd that someone would buy a 'competition' style neck sizing die and use it with variable quality brass, but when you think about it, it makes perfect sense. If you're using top quality brass you use the smaller decapping pin sleeve, and if you're a redneck with a mixed batch of brass, you can still use the die with the expander ball in place.