RCBS Neck Sizing die.....expander ball off center..

SEHunter

New member
This die has sized around 100 cases. I just realized the expander ball/decapping pin piece is warped enough i can see it and feel it when i spin it in my hand while holding the expander ball area. I dont want to completely remove it but i have heard over the years of leaving the nut loose so that the expander ball will center itself. Is this a good alternative to do when using these type of neck sizing dies?
 
ive noticed the same problem with my rcbs fl and neck dies. if you take off the die's lockring and roll it on a flat table theres always heavy runout visible. i dont know if its really an issue or not since by the time the case mouth reaches the expander, the case body has some wiggle room in the die and shell holder, but it still drives me crazy. every time i use those dies i'd turn the stem a fraction of a turn and tighten the small lockring then roll on the table again. it sometimes took many tries to get minimal looking runout. i since have switched to redding dies and have a much easier time getting my expander rod centered. usually bang on first try when i check using my roll test.

is this the problem your having or is your rod acutally bent itself?
 
I think the rod itself is bent. What you do is a good idea but i think that somehow the rod is bent because i took it all the way out and when i use one hand to spin it, while the other is feeling the area where the expander ball is, i can feel the warp in it as i spin it around. I dont know how it could have happened because i lube properly and i have never dropped the die.

I guess i will try to order one. I like the idea of the expander ball being loose so it can center itself but these dies were not designed to be used like that so i dont know if i will only be createing another problem for my self. Does the expander ball screwed on the threaded rod? If the bent part is the same on most of the standard fl and neck dies, i may order several to have.
 
To anyones knowledge, does the decapping pin/expander stud on these dies or similar dies have the reputation of being slightly bent or is it usually always user error? It is possible that i had it set too low and hit the case with the expander ball.

As far as using the die with the expander ball loose, i have been second guessing that because it could allow the decapping pin to hit off center and break so i think i need to replace it.
 
Originally Posted By: SEHunter It is possible that i had it set too low and hit the case with the expander ball.


It's very likely that's what happened. I did it on a .243 Redding die a while back.
 
This gave me the initiative to check all my dies(All RCBS with expander/decapping rods). One thing i noticed right off the bat is that after i took the expander ball off, its clearly visible that the holes are not centered in the expander ball where the decapping pin passes through so if spun, they will look bent. I have a 30-06 neck sizer and 30-06 fl sizer and a .300 Wby. neck sizer and then the original questionable die, a 22-250 neck sizer.

Im hoping the decap/expansion rod on the three .30 caliber dies is the same and fits all, as well as the expander. They all look similar when compared with minor differences that may be due to them being 10 years or so different in age. I think they are interchangeable. The expanders, although slightly different in appearance should all interchange with the 30 cal. dies because they are all .30 caliber. If the same, im going to order two new rod assemblies for future needs and another assembly fir the 22-250.

From now on, i am definately going to pay closer attention to setting it up. Also, after inspecting in my hand how the expander free floats when leaving the top nut loose, it seems this could greatly help run out thats associated with the expander ball.
 
There is going to be a certain amount of slop the design. Since the expander ball does it's job as the case is comming out of the die it needs to self center. It does, however, need to be close enough that the decapping pin always finds the flash hole. As long as it is working this way I wouldn't worry about it.
 
Guys, thanks for all your advise. FW707, thanks for going to the trouble to post the info on the Forster dies. I havent seen that design before and it makes alot of sense to reposition the expander ball to where those guys have it.

I called RCBS earlier and without any question, they are sending me a new rod for my 22-250 die and when i mentioned that two of my other 30 cal dies looked warped, they are sending me two of them and throwing in 5 decapping pins, all this free of charge and with not the first question. Have to say i am blown away with their service.

I think i have a plan that i will try for now...im going to buy the Lee Universal decapping die and from now on, i will be decapping all of my cases with this die before any other step, then tossing them in the tumbler. I plan to remove the decapping pin from my RCBS sizing dies and leaving the expander rod/ball loose at the adjustment nut so that it will center itself and i will not have to worry about the decapping pin being aligned since it will be gone. Sounds like it should be a decent alternative.

Im also going to start doing a much better job cleaning the inside of the necks and will start experimenting with the dry mica lubricant. Sometimes, it feels like the One-Shot lube i use doesent cover the inside of the necks that well. If i can find it, i read over a post somewhere where a guy says he polished out the expander balls in his dies and it helps reduce friction which should reduce some head space issues i have had in the past. At the time, i didnt know enough to know that improper lubeing will cause this.
 
Last edited:
Originally Posted By: skidooracer_99ive noticed the same problem with my rcbs fl and neck dies. if you take off the die's lockring and roll it on a flat table theres always heavy runout visible. i dont know if its really an issue or not since by the time the case mouth reaches the expander, the case body has some wiggle room in the die and shell holder, but it still drives me crazy. every time i use those dies i'd turn the stem a fraction of a turn and tighten the small lockring then roll on the table again. it sometimes took many tries to get minimal looking runout. i since have switched to redding dies and have a much easier time getting my expander rod centered. usually bang on first try when i check using my roll test.

is this the problem your having or is your rod acutally bent itself?

After i took 4 of my RCBS sizeing dies apart, i noticed the hole in the expander ball that the decapping pin passes through is visibly of centered and that alone gives the impression that its all bent up but yours still may be pretty straight. If you take the rod out then remove the expander ball so that you can remove the decapping pin then screw the expander back on without the pin, you can roll it across a flat surface and you should see for sure if yours are straight, which they probably are.
 
Back
Top