I've seen the topic of case neck runout come up from time to time, so that got me wondering about my own loads. I decided to check my case necks before and after resizing. Most of the time when i read topics covering this subject, full length dies with exspander balls are offten suspected.
I checked brass fired in my chamber this hunting season with a sinclair concintricity gage. I then resized the necks in a redding full length die with exspander ball, and checked again. I found that most all my brass once fired in my chamber had a neck runout of .001 - .0015 I had one case with nearly .002. After resizing i find that most all are either a few tenths of a thou, to .001.
I conclude that my full length resizer must have a stem running true with the exspander not pulling the necks crooked. If anyone sees a flaw with what im doing, ease edjucate me. So far I've been happy with rhe reaults. Video link posted bellow.
I guess the only portion of this I could question is will the stem stay centered after hundreds and hundreds of FL sizing. I have noticed over decades, that the stems get off center. I won't try to diagnose why, but it does happen. You are doing exactly what you need to do, checking run out.
I personally do what Mule Deer suggested, and run the expander plug way up in the die. Then I use the Lee neck die. I usually gain about half a thousands by sizing the neck.
Your results are about as good as it gets, but just keep on checking for run out.
I guess the only portion of this I could question is will the stem stay centered after hundreds and hundreds of FL sizing. I have noticed over decades, that the stems get off center. I won't try to diagnose why, but it does happen. You are doing exactly what you need to do, checking run out.
I personally do what Mule Deer suggested, and run the expander plug way up in the die. Then I use the Lee neck die. I usually gain about half a thousands by sizing the neck.
Your results are about as good as it gets, but just keep on checking for run out.
I've noticed that in the past with a 7mm Rem Mag. I ordered a new stem, and after a little trial and error I was able to get back to making straight necks. I'll have to investigate Mule Deer's suggested technique. Sounds interesting. Right now I'm afraid to mess with it since I seem to be getting straight necks as it is.
Sometimes, it's just the sizer body - whether it's a FL or NK sizer. Been having a hell of a time with a Redding 35 Whelen neck sizer. Ran thru all the diagnostics. With the expander (about the size of a bull's prick) in, I was averaging about 10 thou runout after sizing. There was clearly a problem with the expander plug being caddywhompus with the stem. Tried the sizer off an RCBS FL die and cut it in about half. Finally, I just sized necks in the die body only. 4 thou every time. I could be 3 thou if I turned the case 90 deg and tried again.
The die is going back to Redding for their analysis and hopefully replacement. Just about ready to have Lee make me a custom Collet Die.
Sometimes, it's just the sizer body - whether it's a FL or NK sizer. Been having a hell of a time with a Redding 35 Whelen neck sizer. Ran thru all the diagnostics. With the expander (about the size of a bull's prick) in, I was averaging about 10 thou runout after sizing. There was clearly a problem with the expander plug being caddywhompus with the stem. Tried the sizer off an RCBS FL die and cut it in about half. Finally, I just sized necks in the die body only. 4 thou every time. I could be 3 thou if I turned the case 90 deg and tried again.
The die is going back to Redding for their analysis and hopefully replacement. Just about ready to have Lee make me a custom Collet Die.
I always argue for a replacement when my die's do not work as per the manufacturers instructions. .010 of runout is a lot. Considering the luck i have with reddings die's i figure my chances of getting a good one are pretty high.
Hope you get a satisfactory resolution to your problem.
