Cartridge Base walks in Shellholder when seating

[antelopedundee]

Try holding the case against the shellholder with your finger for as long as you can while seating the bullet. Just don't squish your pinkie by mistake. I've often wonder why some enterprising person [or company] hasn't devised some sort of spring loaded device to hold the case firmly against the shellholder while seating.

 

[Lionel Boyd Johnson]

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 formed the habit of gently pressing the case into the U of the shellholder while operating the press handle. When the case is about 3/4 into the seating die, I remove my finger and complete the stroke if using a match seating die with floating neck support; or make three partial seating strokes rotating the case about 120 degrees between strokes. During the first two strokes, I can keep my finger in contact with the case. -Ed

 

[HuntingBronco]

I thought shell holders were meant to be a little loose fitting, especially if the die does not float. Wrong?

 

[epoletna]

There's loose and then there's loose. Some play is necessary, but the case must be held in alignment with the die.

 

[WapitiBob]

Get a competition seater and move on.

 

[jdyoung]

Is this brass new or used ?

 

[johngibbs222]

Ensure the press is mounted perfectly flat or with a very slight "lean" toward the back of the shell holder only 1 or 2 degrees. Even a slight lean toward the front of the shell holder will cause the case to walk, I set mine with a spirit level as once it actually caused the decap pin to bend.
But this was with an RCBS shell holder in a lee turret press.

 

[DrSteve]

You mention that you use the same shell holder for other chambering's. Do the cases still walk around when loading with different dies? You should be able to screw another seater die in, and put a loaded round for those dies and watch it..

I don't remember if it also does it with other calibers.

 

[DrSteve]

Is this brass new or used ?

New.

 

[slikmrc]

Sounds to me your die is doing as it was designed to do which is to hold the case concentric. Being new brass I would mark the cases that are having the issue, fire them and see if this cures the problem.

 

[Russ661]

Does the brass move in the same direction every time it walks? If so I would recommend you turn the shell holder 90 degrees and try again. If it still walks in any direction I'd say you have an out of tolerance shell holder.

 

[DrSteve]

Does the brass move in the same direction every time it walks? If so I would recommend you turn the shell holder 90 degrees and try again. If it still walks in any direction I'd say you have an out of tolerance shell holder.

That's a good idea. I'll try it next time I seat bullets.

 

[mudflap621]

To me seems like the die is aligning the case. Maybe try using an o-ring to free float the die and see if it changes. On my Mec press there is a lot of play in the shellholder and this lets it slide around to center the case in the die.

 

[Rflshootr]

Remove the shellholder from the press and clean the recess that the shellholder slides into. Also clean the inside of the shellholder groove, both with a Q Tip. Then make sure it seats in the ram correctly.