Redding FL/Bump dies and camming over
- Thread starter SS427
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jonbearman
I live in new york state,how unfortunate !
If you have more than one shellholder you can measure the height. They do very a bit from all the vendors and from the same vendors as well. You can polish the top of the shellholder on a flat surface with wet or dry silicon carbide paper. Or go to sinclairs and get a set of redding shellholders and of the 5 you get they are smaller by .001 thou with each one so you can get the depth. They are called competition shellholders I believe, but you cant miss them as they come in a set.
I have to cam-over my press to bump the shoulder even 0.001". FWIW, Redding T-7 press and Redding type-S FL dies. Same for every caliber I load
I believe the competition shellholders only come it plus sizes. If you can't get enough bump you can sand one down a hair. I put mine in a drill press and sand on a flat surface. It could be the die. They do vary and if you measure a couple you find one that works. It could be the die and your chamber could be minimum headspaced. Matt
Is this typical? I'm wondering if my shell holder might be a little on the thick side.
Measure the deck height of your shell holder, the deck height should be .125". And as always, the case could have more resistance to sizing than the press can overcome. When sizing make sure the shell holder makes it to the bottom of the die when the ram is raised.
When the case work hardens annealing will solve the problems of sizing. I have presses that cam over, I have presses that do not cam over.
F. Guffey
Measure the deck height of your shell holder, the deck height should be .125". And as always, the case could have more resistance to sizing than the press can overcome. When sizing make sure the shell holder makes it to the bottom of the die when the ram is raised.
When the case work hardens annealing will solve the problems of sizing. I have presses that cam over, I have presses that do not cam over.
F. Guffey
bigedp51
Otter
I have been reloading for over 46 years using the same Rockchucker press and having the press cam over, and the press is still going strong. I also use the competition shell holders because you do not need to touch or readjust the die to adjust shoulder bump.
Below is a RCBS shell holder on the right and a competition shell holder on the left. The competition shell holder is labeled +4 meaning the deck height the base of the case rests on is .004 lower than the RCBS shell holder. (meaning .004 "LESS" shoulder bump and the case .004 longer in headspace length) The top surface of these competition shell holders are all the same height which means you change the shell holders to adjust shoulder bump "without" touching the die.
To get more uniform shoulder bump I pause at the top of the ram stroke for 3 to 4 seconds and let the brass know who is the boss and less brass spring back. Due to the age or type manufacture of the cases and brass spring back using these shell holders makes shoulder set back a breeze.
NOTE: The only time I ever lapped or shortened a shell holder is when you have short chamber headspace and a die on the long side the would not push the shoulder back even after making hard contact with the shell holder and reaching cam over.
Below is a exaggerated illustration of full length resizing, look at the blue, red and green dotted lines below. As you can see the case shoulder location increases before the shoulder of the die makes contact with the cases shoulder. So get the Redding competition shoulders and don't look back.
I have been reloading for over 46 years using the same Rockchucker press and having the press cam over, and the press is still going strong. I also use the competition shell holders because you do not need to touch or readjust the die to adjust shoulder bump.
Below is a RCBS shell holder on the right and a competition shell holder on the left. The competition shell holder is labeled +4 meaning the deck height the base of the case rests on is .004 lower than the RCBS shell holder. (meaning .004 "LESS" shoulder bump and the case .004 longer in headspace length) The top surface of these competition shell holders are all the same height which means you change the shell holders to adjust shoulder bump "without" touching the die.
To get more uniform shoulder bump I pause at the top of the ram stroke for 3 to 4 seconds and let the brass know who is the boss and less brass spring back. Due to the age or type manufacture of the cases and brass spring back using these shell holders makes shoulder set back a breeze.
NOTE: The only time I ever lapped or shortened a shell holder is when you have short chamber headspace and a die on the long side the would not push the shoulder back even after making hard contact with the shell holder and reaching cam over.
Below is a exaggerated illustration of full length resizing, look at the blue, red and green dotted lines below. As you can see the case shoulder location increases before the shoulder of the die makes contact with the cases shoulder. So get the Redding competition shoulders and don't look back.
reloaders that have been reloading for 45 + years have equipment that has been with them for that many years. Pictures you have posted include newer equipment.
Cam over presses, and claims, there are a lot of reloaders that qualify for membership in the claims department. Cam over can be measured in thousandths. I assisted a reloader, our average age is 80, his A2 RCBS press had .017" cam over. His shell holder failed to touch the bottom of the die when the ram was raised, the gap between the top of the shell holder and bottom of the die was .016".
F. Guffey
Cam over presses, and claims, there are a lot of reloaders that qualify for membership in the claims department. Cam over can be measured in thousandths. I assisted a reloader, our average age is 80, his A2 RCBS press had .017" cam over. His shell holder failed to touch the bottom of the die when the ram was raised, the gap between the top of the shell holder and bottom of the die was .016".
F. Guffey
For consistent shoulder bump dimensions, you should always set your die to firmly abut the shell holder, no cam over. To adjust the amount of bump use a competition shell holder set. Each shell holder reduces the amount of bump by .002". Use a Redding shell holder with your Redding dies and RCBS with your RCBS. They will vary in amount of bump according to brand. If you're not getting enough bump try a different brand or sand down the shell holder.
bigedp51
Below are the RCBS instructions for die setup, granted this is to ensure all resized cases will fit any rifles chamber and can over resize your cases.
"BUT" when the die makes hard contact with the shell holder with the press reaching cam over, any slop in the press is eliminated and more constant resizing is achieved. And this is "WHY" Redding makes the competition shell holders so the press can cam over with the shell holders controlling shoulder bump. If the dies are not setup to cam over any slop or wear in the press will cause variations in the resized case shoulder location.
Below, cam over is the key word.
Below is a RCBS .223 die, it has a Lee lock nut with a rubber O-ring that allows the die to float in the presses threads and self center when finger tight. The decapping-expander button is a Forster unit that allows the spindle to float and self center in the case neck. This die and all my dies reach cam over and the die as pictured below produces very little runout.
The Forster unit on the right lets the expander button enter the neck of the case while the neck is still in the neck of the die. The rubber mounted expander button self centers in the neck and thus produces far less runout.
Cam over eliminates any alignment and flex problems with the press and as long as the die can float and self center in the press all that is left is the shell holder and the die controlling case uniformity during the sizing operation.
"BUT" when the die makes hard contact with the shell holder with the press reaching cam over, any slop in the press is eliminated and more constant resizing is achieved. And this is "WHY" Redding makes the competition shell holders so the press can cam over with the shell holders controlling shoulder bump. If the dies are not setup to cam over any slop or wear in the press will cause variations in the resized case shoulder location.
Below, cam over is the key word.
Below is a RCBS .223 die, it has a Lee lock nut with a rubber O-ring that allows the die to float in the presses threads and self center when finger tight. The decapping-expander button is a Forster unit that allows the spindle to float and self center in the case neck. This die and all my dies reach cam over and the die as pictured below produces very little runout.
The Forster unit on the right lets the expander button enter the neck of the case while the neck is still in the neck of the die. The rubber mounted expander button self centers in the neck and thus produces far less runout.
Cam over eliminates any alignment and flex problems with the press and as long as the die can float and self center in the press all that is left is the shell holder and the die controlling case uniformity during the sizing operation.
I measured the deck height of my RCBS and Redding shell holders and they all measure .125, with the exception of one RCBS holder I used in my priming tool and it measured .126. Looks like I'm in spec with those. (And if they all measure the same, I don't see a reason why I can't use an RCBS holder with a Redding die and vice versa.)
RCBS clearly state to set up their dies so they cam over. Redding on the other hand suggests you snug the die against the shell holder, but don't say anything about adjusting it so it cams over. This setup with the Redding dies give me zero bump, thus the reason I set them up to cam over.
If a garden variety shell holder measures .125 from deck to top of holder, is the measurement of the +.002 competition shell holder .123 or .127? Unless I'm inverted in my thinking, I would need a .123 deck height.
My concern is damaging the die but doesn't sound like that is an issue.
RCBS clearly state to set up their dies so they cam over. Redding on the other hand suggests you snug the die against the shell holder, but don't say anything about adjusting it so it cams over. This setup with the Redding dies give me zero bump, thus the reason I set them up to cam over.
If a garden variety shell holder measures .125 from deck to top of holder, is the measurement of the +.002 competition shell holder .123 or .127? Unless I'm inverted in my thinking, I would need a .123 deck height.
My concern is damaging the die but doesn't sound like that is an issue.
CatShooter
JRS said:
The presses are "O" frame - and when you use a force from the bottom, the top of the "O" tends to bow up. So if you set the die up on the shell holder so it just touches, and then run a case up into the die, the top of the press gets pushed up from the force of the case, and you can actually put a feeler gauge between the die and shell holder.
By setting the die up so there is so much forced required to run the case up, it assures that the case process is fully done, even if the press top is bowed up.
It's actually there to make up for the poor tolerances most are built to. The Lee Classic Cast is bored in one shot, rather than 2 separate stages. It's tolerances are closer than any production press made. It has no "cam over", nor do the very well made custom presses, such as the Hood/Crawford single or double presses, Harrells combos, Ulrich, etc,etc.
BTW: You aren't going to "bow up" the top of the press. You might use enough force, somehow, to cause one of the verticals to crack or break. If you were able to actually stretch the frame, you would have to reset your die each and every time you used it. It isn't brass, nor rubber. The press isn't going to rebound.
BTW: You aren't going to "bow up" the top of the press. You might use enough force, somehow, to cause one of the verticals to crack or break. If you were able to actually stretch the frame, you would have to reset your die each and every time you used it. It isn't brass, nor rubber. The press isn't going to rebound.
Unless I'm inverted in my thinking, I would need a .123 deck height.[/quote]
Use a feeler gage between the deck of the shell holder and the head of the case. A reloader can shim the head if the case as much as .012" when using a RCBS shell holder. I use this method when forming cases for short chambers.
Using the feeler gage increases the presses' ability to overcome case resistance to sizing.
F. Guffey
Use a feeler gage between the deck of the shell holder and the head of the case. A reloader can shim the head if the case as much as .012" when using a RCBS shell holder. I use this method when forming cases for short chambers.
Using the feeler gage increases the presses' ability to overcome case resistance to sizing.
F. Guffey
The rational was long ago and forgotten by almost everyone.
F. Guffey
Forgive, 'forgotten'. that would imply they knew what they were talking about, in the beginning a 'bump press' cammed over, a non-bump press did not cam over, again, I use the Rock Chucker presses to operate my Piggy Back 11 loaders ??? ??? ???
F. Guffey
Otter said:
It is typical for me using my old RCBS Jr. Press purchased in the late early 70's.
Let's keep this simple. Your post suggests that you are measuring shoulder set back - that's the right thing to do. As long as you are measuring shoulder set back to assure that you are not over sizing the case, I see no problem with "cam over".
It's been on the market for quite some time now. It happens to be the WTC (Warner Tool Company)die
A good friend to P.O. Ackley, out in West Texas, made dies for rifles he made. He made what I call stackers. He had an apprentice, the young man decided to go to college, little did he know there were to professors that were guns smiths. Long story, he signed up for their classes. Then one day he made the mistake of telling the two smith/professors what his gunsmith said. As expected they responded in a manner rather rude.
It was not long before the smith from W. Texas came for a visit. He wanted to know what it was they said he could not do. The two professors were impressed. He made reamers for chambers in rifles he built and he made the dies.
F. Guffey
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