case neck runout

[stevesmith]

i have brand new never fired 338 lapua brass that i purchased and loaded and checked runout before and after seting the bullet.. 95% had less than .001 a few had .002..fired them with zero problems. got almost perfect accuracy at 100 yards.. cleaed the brass full length resized checked for trimming to 2.714 cleaned primer pockets reloaded them 2nd time pressed bullet and tested runout on case and bullet..some of them had as much as .006 runout on the case neck..can anyone tell me if i caused this if so what did i do??? and what can i do to repair the problem so i dont do it again..ang suggestions would be greatly appreciated...

 

[Bill Johnson]

One of the biggest causes I've run across is setting up the resizing die. The instructions generally tell you to set the decapping pin for so much protrusion below the die and lock it down. That thing has loose threads 2-3 inches from the other end! I've done that and had the decapping pin completely miss the primer hole. If you do that and end up with concentric necks, I'd go out and buy a lottery ticket because it's your lucky day!

Instead, leave the locknut loose, run a case into the die to the point the neck sizing button is about midpoint in the neck, then lock it down. HTH.

 

[moombaskier]

Most likely caused by the expander ball being pulled through the case neck. Try sizing one and rotate the case 90 degrees or 1/4 turn and resize it again and see if that helps. I also rotate the case while seating the bullets. Also lube the case necks inside. My Forster dies give me less than .001" runout due to when the expander ball is pulled through the neck.
How was the runout before you sized them? Hopefully not an out of round chamber!

 

[Huntersam]

I'm new to this site but have been reloading since 1972, I'm getting old. I had this problem a few times. One time it was the press that was out of line. The co. replaced it but I have better concentricity with my Forester press than my other one's. If your expander has a lot of drag when you are pulling it out of the neck it can get your necks out of line. You can put it in a drill and take it down about .002 and then polish it and I use mica on the inside of the necks. This can help a lot. Also making sure your die is square with your ram in your press.

 

[stevesmith]

Most likely caused by the expander ball being pulled through the case neck. Try sizing one and rotate the case 90 degrees or 1/4 turn and resize it again and see if that helps. I also rotate the case while seating the bullets. Also lube the case necks inside. My Forster dies give me less than .001" runout due to when the expander ball is pulled through the neck.
How was the runout before you sized them? Hopefully not an out of round chamber!

i found my problem being that i had the lee die set lock rings to be to tight not allowing the dies to align them selves when pressing the shell up for decapping and resizing. once i adjusted both the resizing die and the seater die my run out is less than .002 so im all good with that..
thanks for your input and i appreciate all the input i can get..

 

[stevesmith]

I'm new to this site but have been reloading since 1972, I'm getting old. I had this problem a few times. One time it was the press that was out of line. The co. replaced it but I have better concentricity with my Forester press than my other one's. If your expander has a lot of drag when you are pulling it out of the neck it can get your necks out of line. You can put it in a drill and take it down about .002 and then polish it and I use mica on the inside of the necks. This can help a lot. Also making sure your die is square with your ram in your press.

all the above plus allowing the lee dies to align themself took care of the problem..
thanks for your time and help..
have a wonderful day..

 

[dig]

Floating your dies with rubber "O" ring helps, also polish your expander ball I put a high polish on them, chuck it up and use some polishing compound. Lube your case necks like everyone said. Lots of drag equals runout so eliminate the drag.