Cam over

[Link]

If you decide to not cam over how do you setup your dies to make sure your die is square to your shell holder? [ the die has so much slop in the threads of the press ]

thanks Link

 

[357Mag]

Link -

Howdy !

Random thoughts:
- There's a plethora of great dies offered these days, that feature a sliding sleeve that " holds " the case ( Hornady " Custom Grade New
Dimension " seater die, LEE " Collet Neck Size " die; etc.
IMHO - these help moderate any potential negative effects of the die not being " square " w/ the press.
On a " Bonanza " type press, the face of the case' rim is basically free to transition to a happy spot; as the shell holder plates close
around the rim. With features like these present w/ many reloading operations, I'm not convinced the " squareness " issue looms as-
large-as it once might have.

- When bumping shoulders ( say .001" ), how much of an issue could die " squareness " really be ?

As regards " cam over ":
- There are some dies that don't require / won't tolerate " cam over ", the LEE Collet NS die being one example.

- In theory, the new-wave interrupted thread " insert " systems ( like Hornady's " Lock 'N Load " ) should contribute to less die thread
wear; with extended die use.

- Any reloading tools/ components that are obviously " worn ", should be replaced.


With regards,
357Mag

 

[Lapua40X]

You could use a machinist square test block between the bottom of the die and the top of the shell holder and either run an ultra bright light or ultra thin feeler gauges to check the clearance. Or try the poor man's method with a piece of plastigauge ® . But then you'd have to make sure the bore of the die was perfectly square with the base of the die in the first place.

 

[Link]

Thanks Gentlemen.

I should have added I have Redding comp dies. And a Rockchucker press.

How about cam ing against a spacer like a dime , then tighten the lock ring?

later Link

 

[243winxb]

Redding Competition Shellholder Sets

 

[Link]

Redding Competition Shellholder Sets

I got 1 set of those however a lot of people say cam over is not necessary, or shouldn't be done ?

 

[bigedp51]

Redding Competition Shellholder Sets

I got 1 set of those however a lot of people say cam over is not necessary, or shouldn't be done ?

The Speer reloading manual No.9 has a chapter entitled "Modern Benchrest Reloading Techniques" that has a good section on setting up your dies. The manual is dated 1974 and the instructions are geared toward standard grade resizing dies and standard RCBS dies are pictured.

This is where the Redding Competition Shellholder Sets come into play because this setup adjustment requires the shell holder to contact the bottom of the die. And with the Redding shellholders you still control shoulder bump.

With the dies lock ring loosened and backed off adjust the die until the die contacts the shell holder and the press cams over. Then place a lubed case in the shell holder and raise the ram again until the press cams over and tighten and lock ring in position.

With the shell holder pushing upward on the die and the lubed case in the shell holder the die is centered in the threads of the press. If you do not adjust the die to cam over and tighten the lock ring, the die can be locked down off center in the threads and even be tilted. The coarse 7/8x14 threads have a lot of slop and leave room for a misaligned die in the press.

The chapter also covers how to center the decapping rod/expander button in the press. And if you study the Lee Collet die you will understand "why" this produces less runout.

Today you will see people placing a rubber o-ring under the lock ring that allows the die to "float" and be self centering in the press.

 

[BoydAllen]

If you are going to use a spacer to put pressure on a die to square it up, it should be something that has parallel top and bottom surfaces. I believe RCBS made a ring shaped spacer for setting up .38/.357 dies for .357 cases. Having spent some time on the whole concentricity thing, I think that before I worried too much about your die squareness, I would do a test, and see if you can see any difference. There are a number of things that can be done to make straighter ammo that IMO are more important.

 

[K22]

Redding Competition Shellholder Sets

I got 1 set of those however a lot of people say cam over is not necessary, or shouldn't be done ?

Interesting remark - if you don't cam over then how do you set the shoulder back using a full length resizing die. I full length resize all my case and like to set the shoulder back about .002". (All rifles are bolt guns).