I just got a new 25-06AI. I bought a set of Redding deluxe die set including a neck die .. Problem: Using the full length die I get .002 to .003 runout but w/ the neck die I get .004 to .005 or more what gives.,?? I am lubericating both and have checked the expander ball, looks ok and is tight .. Please help.. thanks, Doc Stone

Doc,
Just a shot in the dark.
What size bushing are you using ?
I have a redding neck die too, .006 is max ( from my experience only ) that the bushing will reduce the neck without adding runout.
Measure a fired case, if it's .006 larger than the bushing , that causes problems.
The correct bushing is -.002 to -.003 from the loaded round.
I am using slightly larger, and getting less neck tension ( do not do this if you feed from the mag )

This is just a guess...

Travis F.

Thanks for the reply but I am using the std. neck die that doesn't use the interchangable bushings..Strange to me that a FL die gives less runout than a neck die.. thanks again, Doc Stone

Try removing the expander and see if it helps. The neck dies don`t hold the case while sizeing and if your shell holder is sloppy or expander stem isn`t centered the case can move out of square in the die. I would also reccommend locking the die in the press with a load on it to insure it is square with the ram when sizeing. Lube is also must in your necks to help reduce run out. It doesn`t take much but you need to do it.
You probably will never get a perfect case because of variations in neck wall thickness but you should get run out down to around .002/ .003 with out too much trouble.

Joe has it right. Also make small turns on your expander stem and keep measuring for runnout. (maybe 1/32 turn) keep making small turns and eventually you will get the stem into the middle of the die. BUT the other info is right--it is many times harder to get good runnout from neck dies because the shell is not being held fimly in the die when sizing. I have some redding dies in .340 wby. They are my only set of redding and I bought them because everyone else seems to think so highly of them. I have the same exact numbers as you do--pretty average runnout with the regular dies and worse with the neck die. I bought the redding tapered expander for the neck die and now pretty much use it exclusively to "neck up" 300 wby brass to .340 wby. It seemed to help improve runnout if I made sure I put the shell firmly to the back of the shell holder when sizing. It's real possible if you want to get this crazy (and take an extra step in your sizing) if you took out the expander ball from the redding and used a lyman "m" die to open back the case mouth to the proper dimension. "M" dies are pretty cheap (about $9-12) and they are so very wonderful for Ironing out the case mouths of new brass.
Also-considering the fact that my wby has freebore I'm probably fooling myself thinking there is any accuracy differenc in .001" runnout or .004" runnout!!

Tried removing the expander unit. ,didn't help still .004 or more. Also tightened die to place w/ the case neck up into the neck reduction area, no good either. My FL will resize w/ .001 to .002 runout I'm impressed but hate to resize FL every time as proably will over work the 25-06 brass.. Another question??-- My brass measures about 2.465" after fireforming 25-06 brass. The spec on 25-06AI is 2.494". Will this short brass hurt anything?? much thanx,, Doc Stone

The `06 case has quite a bit of taper to it. Try smokeing a case and part sizeing it with your FL die. You should be able to almost size the full neck with out sizeing the case body. Check and see if your R/O remains low, if so you will be doing the same amount of working as your neck size die is giveing you. The neck die stops a bit above the shoulder normally and you should be real close to the same spot.
I use a feeler guage to measure and reset my FL dies off the shell holder when I use this method with my dies.

This won`t help with the neck die but it`ll get you loading until you get it figured out, or decide you don`t really need it.

IMO,your short cases should be OK, just keep the carbon / copper cleaned out of the neck & throat area when you use them. Others may or may not agree me on this.........Joe

I have had this disturbing problem myself. The runout is usually introduced by the expander button as it backs out through the neck. In that respect, I agreee with the other fellows that cited this problem. I cured mine by doing the following: 1-buy the carbide expander button 2-lube the inside of the case necks, even with the carbide button and 3-to align the decapping rod, pull the cartridge back out until the expander ball just barely engages the neck (that will hold it centered, and then tighten the locknut.

I have, on occasion, allowed my decapping rod to float by not tightening the locknut. It helped, because the rod then follows the flow of the brass better, but you need to continually check the rod to see that it does not shift too far sideways or up and down.

Geo.

I am experimenting to solve this problem by removing the neck expander from my FL die and neck sizing after FL sizing with a Lee collet neck sizing die. Seems this is a popular way to go as Lee neck sizing dies are getting hard to get without back ordering.

Doc Stone:

You're getting some good advice. I think, though, that you would be better off using the full length die rather than worrying about neck sizing. Do a search back a few months on what Hot Core calls PFLR. He calls it partial full length resizing. I call it proper full length resizing. He explains it better than I can. You're actually fitting the case to your chamber by feel. I've beenn doing this for years. Its easy and in most cases more accurate than using a neck die with its lack of support for the case.

As for the short cases: I've shot cases .025 short. I don't think they will get you in trouble. In my mind it would be like a bit of freebore. You're pressure and velocity may be a bit lower but probably not noticealbe. I'm not really sure, though.

knobmtn

Just another comment to further confuse the issue.

Be aware that what you are measuring has an effect on the measurement ( DUH ! )

If you are measuring the outside of the neck for runout, the amount of visible runout will change when you add/subtract the expander assembly.
It does not actually change, it is an illusion, just like the magician making the airplane dissappear. You are looking at somewhere it is not.

Outside vs. inside...

An FL die with expander will true the case to the body, and show less runout than a neck die without an expander.

It has to do entirely with the method of measurement.

The only part that matters a whole bunch is the hole the bullet goes in, not the outside of the neck.

Hope this confuses somebody as much as we are all confused by indirect measurement of anything.

Travis F.

Read this article by John Barsness Factors In Accuracy (link) It explains the reason a FL die tends to size straighter than a neck die.

I originally tried to not to make the above post too long.
I also made it damn near not understandable.

Sorry.

Brass wall thickness variance is one thing I did not mention. Even the high dollar euro import stuff has it.

And that's what the difference between the inside and outside is more or less equal to.

Squarely trimmed brass matters more in a necksizer too.
If it is not square, it will not go in straight, and the body will not keep it straight.

I probably talk too much...

Travis F.