Impossible Shoulder bump?

[eaglemike]

You are only reading that when you read your own posts because nobody else is saying that.

I've never seen that said here either. I can imagine a set of circumstances where one might not move the shoulder enough with some combination of parts and chamber dimensions, or mis-adjusted setup. Maybe a thick/wrong shell holder and/or a die body that was reamed incorrectly?
I had a friend get started years ago (late 80's or early '90's) who was told by the shop to screw the die down until it touched the shell holder. He did that, sized a bunch of .223 brass, loaded a few hundred. They were sized too much, so much they went too far into the chamber of his Ruger (IIRC it was a Ranch Model).

A term that I'm seeing here mentioned often by one poster is "cam over." The term I learned was "going past center" - I think that's more or less equivalent to the term "cam over"? I never heard that term until here on CG. I think all the metallic loaders I've ever owned did that to some small degree.

[ar15barrels]

A term that I'm seeing here mentioned often by one poster is "cam over."
The term I learned was "going past center" - I think that's more or less equivalent to the term "cam over"?

Yes.

[pennstater]

Talks in circles, he does.

Yup.^^^

MLC

[fguffey]

pennstater.

When I tell you a chickens dips snuff, don't argue, first catch the chicken and then determine where it carries the can.

In the very beginning I said I find it impossible to move the shoulder back when sizing a case. When forming and or sizing the shoulder I finish with is not the same shoulder I finish with. And then came the bumpers, the bumpers insisted they could bump the shoulder back; it was then I said I find it impossible to bump the shoulder back and I said 'bump is a function of the press.

No one on 5 different forums came up with a way to move the shoulder back, very few of them knew what direction the brass moved when forming and or sizing etc. etc. When I size and or form a case the shoulder becomes psrt of the neck and part of the case body becomes part of the shoulder. it should not be but all of that is beyond a reloader comprehension.

F. Guffey

[bigbossman]

When I size and or form a case the shoulder becomes psrt of the neck and part of the case body becomes part of the shoulder. it should not be but all of that is beyond a reloader comprehension.

F. Guffey

So - you bumped the shoulder back? Got it.

[thegiff]

I think you are arguing definitions and different names for the same thing. Bumping the shoulder back to everyone now , which is in the last 30 years, means two things at the same time. Resizing the case, and pushing the gauge line of the shoulder of a bottleneck cartridge down by some measurable amount.

And every reloading book out there for the last 30+ years talks about brass flow, which is also known as case stretch, which moves brass up into the case neck. Hence needing to trim the end of the case now and then.

The common definition of bumping the shoulder is moving the gauge line of the shoulder down, I think you are arguing that the brass flows up when that happens and that the original shoulder is now higher than it was and is now reformed. OK, so we trim it off and move on. And at some point the bottom of the case is too thin and the case is tossed in the trash or recycled before the case head separates. These are all known as part of brass flow and it seems to me the same repeated statements are going over well-known issues.

Cam over, going over center, etc. are also different names for the same feature of high-force presses. OK, why argue over that? You can get several tons of force in that last .005" stroke of the press with little effort, but the arguing over what words were used to get there is getting a but old.

Please, go by the common definition of "bumping the shoulder" which is moving the datum.

[fguffey]

A term that I'm seeing here mentioned often by one poster is "cam over." The term I learned was "going past center" - I think that's more or less equivalent to the term "cam over"? I never heard that term until here on CG. I think all the metallic loaders I've ever owned did that to some small degree.

I have three Rock Chuckers, I understand that seems to be an excessive number but two of them are used with progressive RCBS attachments. The 2 attachments have 5 position presses shell plates; the advantage to the 5 position press is the ability to use a powder die and or a lock-out die. If a reloader is using a 4 position press they have a problem if they use a lockout die and or a powder die, meaning it is a one or the other thing, they can use a powder die or a crimp die.

I do not hate to do anything and it would not bother me if I crimped my cases after I finished loading my ammo on the 4 position press, but there are so many winners that find fault with everything.

Back to Cam-over, many reloaders that use Rock Chuckers claim it is a cam over press, if they are using the Rock Chucker with the 5 position attachment the attachment will not have the auto advance feature. Meaning the auto advance attachment has a one-way clutch that prevents the the shell plate from reversing. Nothing I can do about it, ever time my 5 position press reverses direction it destroys the one way clutch.

No one remembers the old automatic transmissions, same thing, when going from reverse to drive stop the car and then remove the selector from reverse to drive, failure could bust the ban and or seal on the piston that controlled the ban, again nothing I could do to change that, that was the way it was designed.

So if the RCBS Rock Chucker was a cam over press, RCBS would have had to design another press for the 5 position attachment, the attachment was called a Piggy Back, and then it became a Piggy Back 1 and the next attachment was called a Piggy Back 2, after that it was possible to update the #1 to a #2.

The Piggy Back arrangement had a height limitation, it would allow for reloading 223 ammo.

F. Guffey

Cam-over was a function of the press, reloader never read the instructions but they insisted on being taken seriously. The instructions suggested the reloader adjust the cam over press differently from the non cam-over press because one press was a bump press and the other press was not a bump press. No one knows when that information was available but any guess that it was written sometime in the mid 50s would be a good guess.

Almost forgot, the cam over press bumped twice, and that is the reason the two presses should be adjusted differently.

F. Guffey

[fguffey]

Forgive, I did not see your second post. Again, I said I have found it to be impossible to move the shoulder back "like reloaders demonstrating their their knowledge of reloading and use of terms.

I said I scribed a line on the shoulder of many cases before sizing them. I said I have never found a scrib line move back toward the head of the case, I said the scribed line always moves tword the neck of the case.

It does not matter how many flowers you use, the shoulder you start with is not the same shoulder you finish with and now you say the datum or scribed line flows forward/toward the neck of the case eventually requires trimming.

And the flow that causes case head separation? I can only guess they have reloaders writing books because the old books suggested the case body locks to the chamber when fired and the case stretches between the case head and case body. I try to avoid making this stuff up.

F. Guffey

[thegiff]

You are describing what is happening with brass flow in different words and talking a bit past others, it took a bit for me to figure out that. This whole conversation is going in repetitive circles.

Correct that if a press cams over completely it will bump 2X, once on forward and once on reverse stroke. My redding turret press doesn't cam over, it stops short. I think it is because the pivot pin is not all that strong, since it has to hold the turret down. So if someone were to grunt on it either camming straight up or over (by revising the stop location) then you could easily apply enough force to break the turret rotation pin. Whereas the O-frame presses like the RCBS can easily take that force.

You seem like a nice guy but there isn't anything new in this thread so I'm out.

[TomReloaded]

Absolutely no one ever has brought up brass flow, nor does it even remotely matter for reloading.

It's not even semantics, it's just being ridiculous.

[smoothy8500]

You are describing what is happening with brass flow in different words and talking a bit past others, it took a bit for me to figure out that.

And we see another reloader has fguffey figured out....

[smoothy8500]

Absolutely no one ever has brought up brass flow, nor does it even remotely matter for reloading.

To be fair, what fguffey brings up is the source of case separation and neck trimming. However, he has to be ridiculous about it.

[bigbossman]

And we see another reloader has fguffey figured out....

Yeah - he's being pedantic and obtuse at the same time. See - he's not bumping the shoulder back per se, he's defining a new shoulder location on the case. The original shoulder is still there, it's just that now it's part of the neck.

That's completely different..

[LynnJr]

This has been explained to the guffster on many many message boards dating back over 20 years ago on benchrest central were he was eventually banned by Wilbur Harris the owner and southeast regional director.

He still to this day thinks we have to measure the necks grip on the bullet in units of Tensions because the vernacular used is neck tension.

Following his line of reasoning cylinder head bolts need to to measured in torques not foot/pounds because we are torquing the headbolts down and not foot/pounding them down.

Then there was the time I was shooting 243 Winchester ammo out of a 30/06 Mauser and the shoulder all but disappeared.

[bigbossman]

cular used is neck tension.

Following his line of reasoning cylinder head bolts need to to measured in torques not foot/pounds because we are torquing the headbolts down and not foot/pounding them down.

Speak for yourself...... I foot-pound the hell out of every bolt I come across.

Oh, and on your .243...... the shoulder was still there, it just changed shape!!