rockchucker press getting old

[spike]

I have a rcbs rockchucker press that is about 20 yrs old.When I raise the ram to the top I can wiggle it left to right but not front to back. I have oiled it periodically since I got it. I am trying to track down some run out problems I am having with some dies but not with others.

 

[NorCalMikie]

email to rcbs.tech@atk.com. They can and will answer your questions. Works for me! HTH. Mike.

 

[Travelor]

I had the same "problem". Mine is 40+ years old.

Sent the press back to RCBS and they re bored the press and replaced the ram. Be sure to tell them that you have a bunch of older shell holders when you send it back and they have changed their dimensions and some older shell holders won't fit. If you do this they will correct the ram to accept the older shell holders.

Great service!!!

 

[BoydAllen]

The "hottest" centerfire Benchrest shooter in the NBRSA Gulf Coast Region, loads with a set of RCBS partner presses that are bolted to an aluminum plate. He has modified these presses by turning down the rams so that cases have more freedom to self align with dies. Another example of the desirability of this sort of thing is the Bonanza/Forster reloading press. The die is secured in the press by a slot that captures the lock ring but which allows lateral float to let the die and case align. These presses are thought to produce ammunition of superior straightness. The one application where a tight ram fit is really needed is bullet making, where excess play can result in undesirable die wear. Tighter isn't always better.

 

[Travelor]

Boyd, I agree with loose can be better and I have a Forser Co-Ax press that works on this principal. But when I purchased some Comp Redding dies, my RockChucker was causing the necks of cases sized to be scuffed due to the misalignment. After RCBS reworked the press, this problem stopped.

The RCBS rep also agreed with you, but I am very happy with the tighter press. Load with the Co-Ax press for my informal BR and formal 1000 yards ammo.

 

[brickeyee]

Achieving tight alignments has always been a double edged sword. You can rigidly hold everything,tough and subject to wear), or you can try and make ‘self aligning’ tooling that can compensate for initial error and wear.
Both methods can be made to work, but using tooling for one type,a Rockchucker) for the other method,floating dies Forster style) is rarely successful. The Rockchucker is not going to have the parallel bearing surfaces needed for the job like the Forster ‘slot’ to float the die. The result will likely be some floating, but not enough,Mr. Murphy will ensure the float is inadequate in the required direction).
I have one Rockchucker I put alignment screws into a couple years ago. They are brass screws in tapped holes that bear on the side of the ram and tighten up the play. It is a real pain to get to tight and straight concurrently, but it holds for a few thousand rounds before needing adjustment again.
It makes a difference on my Kelbly built varmint rifle, but not on much else.