Rock Chucker Bushing

[Old Navy]

I am sure this has been covered somewhere here but I can't find what I am looking for. Does the steel bushing in the top of the Rock Chucker wear enough to cause neck run out during resizing? I am introducing approximately .0005" when resizing my 6 BR cases. My press is 30 years old. The dies a very sloppy fit.

 

[Bill K]

I would not think so, but you might call RCBS tech and ask. They would probably even send you a new bushing, for free, if they believe it would help you, I bet.

 

[acloco]

Five ten thousandths? .0005 (1/2 of one thousandth)

Or...0.005 Five thousandths??

 

[Ned Ludd]

Five ten thousandths? .0005 (1/2 of one thousandth)

Or...0.005 Five thousandths??

I'm curious about that as well. Did you really mean .0005"? Half of one thousandth of an inch runout? If so, I'd ask how carefully you actually measured TIR when the Rockchucker was brand new.

If you really meant .005" runout, I'd contact RCBS directly and see what they recommend you should do to repair, upgrade, or even replace the press. Parts do wear out over time. I'd also check the dies used. To some extent, a tight-fitting die can negate or offset some sloppiness in a press, but if both are loose, the problem will be even worse.

 

[Cecil S.]

No doubt RCBS service is outstanding. Give em a call they will help you

 

[Dusty Stevens]

Actually the more worn the better. Your die is doing the influencing. A press is only there to push the brass in and pull it out. If its tight it can influence the brass and thats opposite of what you want. Looser the better- let your die do the work. Try a different die

 

[JimSC]

I am sure this has been covered somewhere here but I can't find what I am looking for. Does the steel bushing in the top of the Rock Chucker wear enough to cause neck run out during resizing? I am introducing approximately .0005" when resizing my 6 BR cases. My press is 30 years old. The dies a very sloppy fit.

Is it sloppier than the shellholder holding the case? I bet if you put a case in the shellholder and wiggle it you will have about .1 movement in every direction

 

[Mad_Charlie]

Actually the more worn the better. Your die is doing the influencing. A press is only there to push the brass in and pull it out. If its tight it can influence the brass and that's opposite of what you want. Looser the better- let your die do the work. Try a different die

My Rockchucker is 45 years old this year, and it has loaded many thousands of rounds of pistol and rifle ammo. The ram is a little worn and the pivots are too, but
it really does load straighter ammo than when it was new. I use the Redding shellholder sets to avoid sloppy shoulder bump because of the worn pivot pins.
I also have a very nice Forster, but I mostly just do seating with it.

Half a thou ain't much...

 

[JFrank]

Sloppy linkage?
I would think too much internet adjustment like turning the die down another 1/4 turn and the dreaded cam over ...

 

[dgeesaman]

I am sure this has been covered somewhere here but I can't find what I am looking for. Does the steel bushing in the top of the Rock Chucker wear enough to cause neck run out during resizing? I am introducing approximately .0005" when resizing my 6 BR cases. My press is 30 years old. The dies a very sloppy fit.

When the threads are worn, they provide less influence on the alignment and allow the bushing shoulder to square the bushing. I'd say that's a good thing.

 

[Linko]

How about the quick change bushings from Hornady and Lee?

 

[TAJ45]

I bet if you put a case in the shellholder and wiggle it you will have about .1 movement in every direction

Prolly .01 but not .100 -

 

[686 Shooter]

I am no expert and don't want to start a war but I have a question. When a press wears and loosens up would one not need to ensure that all worn parts are moving in a straight line from the time the case enters the die to when it is fully inserted? My thoughts are that if the linkage puts a sideways force on the ram it would cause the cartridge to enter the die on an angle. As well if the die bushing is worn unevenly it could allow the die to cock itself at an angle when force is applied to it. Would either situation not cause run out?

If my thinking is out to lunch please let me know. I'm an old dog that likes to learn new tricks.

 

[dgeesaman]

How about the quick change bushings from Hornady and Lee?

I started using them recently and I like them.

There is vertical play in them but they size consistently. I’m sure if you really want it consistent, you can mark the bushings and install them in the same orientation every time.

 

[Dusty Stevens]

I am no expert and don't want to start a war but I have a question. When a press wears and loosens up would one not need to ensure that all worn parts are moving in a straight line from the time the case enters the die to when it is fully inserted? My thoughts are that if the linkage puts a sideways force on the ram it would cause the cartridge to enter the die on an angle. As well if the die bushing is worn unevenly it could allow the die to cock itself at an angle when force is applied to it. Would either situation not cause run out?

If my thinking is out to lunch please let me know. I'm an old dog that likes to learn new tricks.

Loose is good as long as the press isnt broken and forcing the case in a bad direction. As long as its pushing the case and letting the die do the work its good. If you can push the case halfway in the die, let off the ram and the case is still loose in the shellholder its working real good like if you can move the ram with no pressure on it then its not influencing the case

 

[JimSC]

Prolly .01 but not .100 -

you got me curious so I pulled out the feeler gages. On a Lee shellholder and a Norma 6 BR I had .008 clearance on the X and Y axis. On the Z axis it is unlimited of course so you can slide the case in there. I use a Lee turret these days and it has about .010 horizontal and .008 vertical "slop" in the turret I measured. I don't have a Forster co ax handy to measure the slop in the dieholder assembly but I am sure it is substantial also

The point is once that the case/die has to have some play so it can align and once the case is into a full length die you have a press fit. Clearance or "slop" between the die and the case is necessary to the function of a press and has zero effect on the concentricity of the ammo

 

[rogina]

I am sure this has been covered somewhere here but I can't find what I am looking for. Does the steel bushing in the top of the Rock Chucker wear enough to cause neck run out during resizing? I am introducing approximately .0005" when resizing my 6 BR cases. My press is 30 years old. The dies a very sloppy fit.

I just sent in my old Rockchucker because the linkage is worn and they told me they don't have many parts left.

 

[686 Shooter]

Loose is good as long as the press isnt broken and forcing the case in a bad direction. As long as its pushing the case and letting the die do the work its good. If you can push the case halfway in the die, let off the ram and the case is still loose in the shellholder its working real good like if you can move the ram with no pressure on it then its not influencing the case

That makes sense. Thanks Dusty.

 

[Shooter13]

I started using them recently and I like them.

There is vertical play in them but they size consistently. I’m sure if you really want it consistent, you can mark the bushings and install them in the same orientation every time.

I'm curious about this. I put one in my rockchucker and got vertical movement on the die and it acted like it was re-indexing, anyone else see this? I really liked the concept of being able to put one die and insert another one but not sure now. Not meaning to hijack the thread.

 

[Dusty Stevens]

I'm curious about this. I put one in my rockchucker and got vertical movement on the die and it acted like it was re-indexing, anyone else see this? I really liked the concept of being able to put one die and insert another one but not sure now. Not meaning to hijack the thread.

It can move 1/2” and still be ok as long as it moves to the same spot every time- kinda like a sliding sleeve in a sizing die