Decapping Rod Assembly question


Well-Known Member
Nov 22, 2018
OK, I’ve always used a decapping rod assembly whenever I reload. Been doing so for twenty years. Is it really necessary? I read that it just introduces another variant to throw off concentricity and is not needed. I deprime with a universal depriming die before tumbling initially anyway. Getting more serious about shooting for long range accuracy as of late and just wondering. Thanks


Well-Known Member
Feb 25, 2008
There’s a problem with NOT using the expander, if your die squeezes the neck .008” smaller than bullet diameter, what’s going to bring it to .002” under the bullet diameter for good neck tension?
I have used every tool there is to reload ammo, neck only dies, FL dies, neck only bushing dies, FL bushing dies and in-line dies etc, etc.
Any die that does minimum sizing in ANY direction, including the neck is best.

I find my best concentricity is made using Forster honed neck FL Bushing dies with the expander installed and lubed with very finely ground graphite powder. The die neck only moves the neck .003”, the expander opens it .001” and is perfectly at .002” under bullet diameter. Forster dies are very inexpensive and they will hone to the size you want.



Well-Known Member
Dec 12, 2005
Tucson Az
Bushing dies are nice but used by themselves they could raise a new issue. The neck walls must have the same thickness piece to piece which one reason for turning the necks. If neck walls are not the same size the bushing will yield different neck tensions.

So then you decide to turn the necks to use the bushings without any sizer ball....If the chamber is a SAMMI spec then the expansion of the necks can get excessive if you do more than skim turn 80% or so of the necks.

A better way with variable neck wall thickness brass is to use the bushing and size the necks .001" smaller than the sizer ball dimension and pull the brass past the sizer ball as the last step. This will accomplish the goal of minimal working of the brass for longer life and not induce neck runout.

A fitted sizer die which would size down the neck the appropriate amount, would be a great way to go but that requires that brass neck thickness is the same for all pieces.

So if all this is enough to dissuade you or others from trying these methods, just use your standard FL sizing die with sizer ball. Pay attention to proper lubing and expect the brass to not last as long. Quite frankly most hunting rifles won't see any difference in performance and many of the cases end up with loose primer pockets before the neck walls split due to overworking of the brass.

Pretty crazy huh?


Well-Known Member
Dec 10, 2010
One of the main reasons of neck runout happens when the expander is locked down off center.

The high mounted floating Forster expander enters the case neck when the case neck is held and centered in the neck of the die.

You can use any manufacture of resizing die and remove the dies expander and then use a separate expander die and reduce neck runout.

Dies that lock and center the expander in a collet have far less neck runout than dies that do not self center.

Below a cheaper Lee sizing die can produce less neck runout than a Redding or RCBS die.


Below I installed a modified Forster expander and spindle assembly on my Redding FL .243 die to reduce neck runout. And I can understand why many reloaders complain about expander drag when using Redding's longer expanders.


After testing many brands of dies I think the Forster dies with their high mounted floating expanders produce cases with the least neck runout. If you do not want to buy new dies then use a expander die like the Sinclair expander die with its floating expanders. NOTE, expander dies expand the neck on the upstroke of the ram with the case resting on its "flat" base.


Below as stated in another post the honed Forster FL dies work the case neck the least and produce cases with less neck runout than bushing dies.



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