New to reloading and already hit a snag.

[bigedp51]

If you put an o-ring on your decaping stem between the lock nut and the die body it gives the expander a little play so that your press can pull it through on a straight line, I do it with my redding dies it seems to help the runout a little

Can't do it with Hornaday dies because the decapper doesn't thread in its held via compression

Below is a modified Forster expander and spindle assembly fitted to a Redding full length .243 die. The expander is mounted high and works just like it would in a Forster die. And under the dies expander lock ring is a rubber o-ring to let the expander float.

Bottom line just putting a rubber o-ring under the lock ring doesn't mean it will "center" the expander. On top of this I see no reason to drag the "LONGER" Redding expander through the case neck. "Remember" with the Forster dies the case neck is held and center in the die when the expander enters the case neck.

Below I retro fitted Forster expander and spindle assemblies on all my older RCBS dies to reduce case neck runout. Below the RCBS expander is raised as high as it will move and is still not at the correct hight as the Forster unit on the right.

Before switching to Forster dies I would remove the Full length dies expanders and expand the case necks with a Sinclair expander die. This expands the case neck on the up stroke of the ram and pushing down on the case with it resting flat on the base of the case.

NOTE, if you have any dings in the extractor groove the case will tilt in the shell holder and with a standard die the case neck will be pulled off center on the down stroke of the press. I noticed this when reloading my .223/5.56 cases fired in my AR15 rifles. Meaning the bolts extractor chewing up the case rims and extractor groove.

So again the Forster die holds the case neck and the expander can not pull the neck off center even with dinged up rims.

 

[Rich Coyle]

tag

 

[XOOFP]

Okay,
I have read and re-read several times the last string of comments and I think I am following you guys at least 85% or better. First off I wanted to post a photo of my sizing die, which is a full length die with custom selected bushings (tbd) for the neck. There is a rubber o ring below the locking ring for the dacapping pin vertical adjustment. There seems to be some play horizontally with the dacapping pin. The decapping pin and expander certainly seem to have a small amount of "float" to them. Included are both an elliptical expander and a decapping pin retainer. On the bottom photo you can see it with the expander installed. My calipers tell me the expander is right at bullet diameter (0.284). I have tried to picture how the expander and neck bushings would interface with the case. It seems to me that the expander will of course push through the mouth before the neck bushing attempts to size the outside of the neck. Then the expander will pull back through as the ram lowers again last. So will the expander just "undo" what the neck bushing has just sized as it exits the case mouth? Also, biged, could you clarify for my newbie understanding why the location of he expander vertically makes a difference in runout?

Thanks all of you for your patience,
Josh

 

[Adikted]

If your neck bushing is properly sized you shouldn't be expanding the case at all after sizing. The reason standard full length dies have expanders is because the die has to under size the neck to account for different brass thicknesses, then the expander pulls it out to the "proper" diameter so that the bullet will go in undamaged and have adequate tension.

The reason bushing sizers came about is to prevent working the brass twice and eliminate the expander.
Bench rest shooters tight neck their chambers.
This means that the neck of the chamber is one or two thousandths over bore diameter plus double neck wall thickness. So they're turning all of their necks anyway and bushing selection is pretty straightforward.

They do this to minimize case movement, and send the bullet into the rifling as straight as possible

SAAMI spec chambers have plenty of extra clearance because they have to work for all the different thicknesses of brass so you don't get many benefits from turning necks aside from bullet tension being the same and that's more or less imperceptible with all of the other things going on.

As far as the expander increasing runout, if the expander isn't perfectly centered or if the shell holder is trying to pull the case down tilted the expander can deform the case mouth so that the axis that the bullet seats at isn't the same as the bore axis.

I hope that makes sense

If you're going to get this deep into reloading you're going to need a concentricity gauge otherwise you have no idea what your changes are doing to the ammo.

 

[XOOFP]

[QUOTE="Adikted, post:

If you're going to get this deep into reloading you're going to need a concentricity gauge otherwise you have no idea what your changes are doing to the ammo.[/QUOTE]

I'm looking at them now. Brownella has free shipping over $49.

 

[just country]

morning, lonewolf is totally right, we all learn from experience. OH
Kevin Thompson, we r not turds. very poor choice of words.
GBOT TUM