I remember reading an article in PS about the Redding "Instant Indicator". Somewhere in his prose the author warns against "adjusting headspace length on a fired case by backing the resizing die away from the shellholder as it is a sure means of destroying case-to-case uniformity. Better use Redding competition shellholders". In other words, he's referring to partial sizing with a FL sizer, a procedure I (succesfully) apply since decades. Any idea or comment on the validity of this cautioning ?

Not sure what is behing the author's suggeston to avoid backing off the sizing die and use Redding custom shellholders.

Like you I have been backing off the die for many years. In some cases, as much as .050 to partially size the neck only. Some die manufacturers suggest doing that to avoid over working the brass. Redding shellholders are not that thick to handle a .050 backoff.

With my 22-250, I can tell if I have hit the right die depth as the bolt will give a little extra resistance on closing. Recently have switched to the Redding T-7 turret press to avoid having to reseat the dies each time.

If what you are doing is giving good results, why change a winning formula.
Ron

FlyDevil,
The object behind the Redding Competion Shell Holders is when using them you adjust them by running the ram up to it's highest travel and you screw the sizing down until it touches the shellholder(that's using the regular shellholder for the set-up) and you lock it down. now your sizing die is now set square to the shellholder.
the shellholders come in .002-.004-.006-.008-.010. you start with the .010 holder and work your way down until you get the case to chamber with very slight resistance. i use this method for my M-1 Garand and M-1A and found that it does improve accracy. a lot of guys are under impression that you can just size the neck of a case by using the partial re-sizing method with a F/L die. that is not so. on a F/L sizing die as soon as the die starts the case neck it also starts sizing the case body at the same time. so you are still working the whole case just not as much as you would if you set up the die according to the manufacture instructions. neck sizing dies do not work the case body, just the necks and some will even bump back the case sholder.HTH
Rick

Rich from K.
You explained the Redding shell holder process very well. In effect with the Redding .010 thicker holder, you are moving the die upwards by .010.

You mentioned that you "squared the die" with the ram as recommemded by Sierra, etc. I do exactly what you mentioned but I use a .050 shim between the ram and the die to perform the squaring. The shim is removed and I do the resizing. The only difference is that the Redding shellholder will contact the bottom of the die whereas in my situation the shellholder has a .050 air gap. Can's see that there would be any difference since both dies have been squared.

Agree there can be some sizing of the case in either situation if you are using a FL die. But there will be substantially less resizing being .050 off the die versus .005 or .010 using the Redding holder everything else being equal.

Additionally, I believe the effect of the resizing depends on how big the chamber is or how blown out the case is. My Remington 700P had such a fat chamber it would only shoot semi-accurate (0.5 MOA) if I backed off the die by .050. It seemed that the ridge formed on the neck by being only partially sized help hold the case in the chamber better.
Ron

the info that came with my redding fl bushing die said to back of the fl die 1/3 of a turn from the shell holder, size and see if the case will fit the chamber. A better way to start is put a shim .004" thick (soda can) between the shell holder and fl die, and start there, since correct head space (243win types) should never be more than .005" on the large side. With the die turned out 1/3 the sized case will chamber, but you will have to keep turning the fl die down each time you load,as the brass expand slowly. No, you can NOT neck size with a fl die.

[ 07-06-2003, 19:52: Message edited by: 243winxb ]

Andre, the groups you shoot prove that this guy's caution is, well, merde!!

Thank you guys, interesting discussion. Obviously, my loading M.O. can't be far off considering the groups I get out of my thundersticks. But, as many will understand, I'm always eager to pick up a little something susceptible to shave another hair from my groups. It's all in my head, I know