Cartridge Base walks in Shellholder when seating

[DJohn59]

I run the same combo you are talking about with no problems. I removed the retaining clip for the shell holder and replaced it with a rubber o ring a long time ago. This allows for movement so the shell can find it's happy place of alignment. If you do not have a concentricity problem, then all is good.
Glen Zediker's book "Top Grade Ammo" is a good one to check out. As long as I follow his directions in setting up, I have no problems.

 

[Blackhawk]

I'm using a Forster seating die in my RCBS Rock Chucker Supreme with a Lee shellholder. Sometimes the base of the cartridge will walk out of vertical position when I'm seating. I haven't measured the runout, but it can't be good. I don't think there is anything wrong with using Lee shellholders. Wonder what I'm doing wrong or if anyone has had this

I'm using a Forster seating die in my RCBS Rock Chucker Supreme with a Lee shellholder. Sometimes the base of the cartridge will walk out of vertical position when I'm seating. I haven't measured the runout, but it can't be good. I don't think there is anything wrong with using Lee shellholders. Wonder what I'm doing wrong or if anyone has had this problem?

Just wondering how old is the press and how much use has it seen ?
It is unlikely but over time press rams will and do wear. I have never had one walk quite as much as what you are encountering but I do not use Lee shell holders. I prefer either Redding , RCBS , or Horandy even Lyman , as I never had any issiues with these brands..
If in doubt you can use a magnetic base set up with an indicator to observe first hand how much run out or play if any you have., that is if you are lucky enough to have one that is handy. If not perhaps you may have a friend who is a machinist that will let you borrow one.
Now getting back to your RCBS press.
First off how old is it and has it seen any abuse?
A) Is your press bolted securely down or is it flexing at all?
B) Look at your shell holder is it showing any signs of wear in the corners? It should snap firmly into place when slid into the ram without any slop at all.
C) Is there any play at all in your ram? By that I mean will it wiggle at all while you raise or lower it.
D) Is all your hardware tight or are any nuts etc. loose? Don't forget to lightly oil your ram while your at it. ( Every six months or so I use an automotive spray wax and apply it to all my presses. This will help to prevent rust and oxidation from forming on your press )
E) Check the brass case heads rim thickness using either calipers or flange micrometers . Please note if you have any extractor claw markings or any other signs of unevenness on your cases head and rim. ( This can cause your brass to walk in a shell holder, this becomes more prominent if you are using an autoloader ) discard any that are exhibiting these signs.
F) Use brass from the same manufacturer and lot number . Do not use mixed lots or range brass until you determine what your problems are, and have repaired them. Do not use or reload any military crimped brass as stated above until you locate and repair your problems. The same goes for brass that has been the subject of multiple reloads without annealing.
G) Make certain that your primers are seated at least -.003" sub flush to the case head itself.
If you find anything out of the ordinary please fix it ASAP as any one of the items that are listed can cause you headaches.
Finally as noted in other posts procure a new quality shell holder as after long hours of use they can become warn.
Hope that this will help you.
The Rock Chucker Supreme from RCBS is one of the most reliable single stage presses that you can buy. Just ask me ,I own one and have never had any issiues with it other than the MM priming arm and as well as the rest of the priming system. ( MM = Mickey Mouse )
F.Y.I.
This is what I load all my rifle brass on. I prefer the solidness oF the RCBS Rock Chucker Supreme single stage press to a progressive press.
I have several progressive presses in house . Dillon and Hornady as well as a Lyman All-American come to mind , however the Rock Chucker has always been my go-to press for use reloading rifle ammunition . My progressive presses are reserved for the handloading of revolver and pistol ammunition.

 

[jdyoung]

Is this brass new or used ?

New.

As part of your new brass prep, do you run it through a sizing die of any kind ?

 

[DWier]

I run the same combo you are talking about with no problems. I removed the retaining clip for the shell holder and replaced it with a rubber o ring a long time ago. This allows for movement so the shell can find it's happy place of alignment. If you do not have a concentricity problem, then all is good.
Glen Zediker's book "Top Grade Ammo" is a good one to check out. As long as I follow his directions in setting up, I have no problems.

If you find there is a problem with the press (which I doubt) you might want to look at a Harrell's turret press. However I'll bet a quality shell holder will fix your problem.

 

[joseytoo]

JD300WM, That partially crushed primer would worry me! I really don't like to see those sort of things when I reload. Just MHO, That don't make it right.

 

[Susquatch]

I'm using a Forster seating die in my RCBS Rock Chucker Supreme with a Lee shellholder. Sometimes the base of the cartridge will walk out of vertical position when I'm seating. I haven't measured the runout, but it can't be good. I don't think there is anything wrong with using Lee shellholders. Wonder what I'm doing wrong or if anyone has had this problem?

I've had this problem to some minor degree with every shell holder of every size and brand and every model of press that I have ever used. The shell holder MUST be loose enough to allow the brass to properly align with the die and tight enough to retain it. It is not a problem. It will probably be worse if your press is mounted on any kind of angle and if the bullet is not perfectly balanced on the case mouth before it enters the seating die.

Most of us develop small habits that we use. I always hold my brass against the back of the shell holder with one finger till the case enters the die. That stops it from moving like you describe. I seat the bullet half way, then back off, rotate the brass 180 def, and complete the stroke.

I do the same with my powder scale. Every single time I weigh a new charge I push the knife against the back stop so it's always in the same place. And the list of consistent actions goes on and on and on.