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Run out

I know most real reloaded are ditching expander buttons for mandrel, but the wife has me on a budget so I use what I have. My question is should I adjust the decapping pin protrusion and lock the jam ring down or would leaving the locking ring loose allowing the button to float slightly in the threads and maybe reduce case runout?
 
Depending on your shooting discipline, in my experience, after testing with run out gauges, floating dies or floating expander assemblies, I never was able to identify a significant, if any, change on target using conventional RCBS F/L dies.

Some I know move the expander button up in the die and de-cap separately. I think one of the conventional Forester F/L dies employs this concept. In theory, I should improve alignment, but I have never verified this claim.
 
Lock down.

Die alignment in press- The shell holder must contact the botton of the fl die first.
The tighten the die lock ring for alignment.

Redding competition bushing shell holder set allows the contact & control of shoulder bump.
Lee die? Not to my liking.
My 1970s Lee 223 die, could not push out crimped primers.

For me- Threaded decapper pin, made by RCBS, ty.
 
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How many check runout after running the mandrel in the neck?
The only time I check runout is when I’m setting up a new system, like a new die, or press. I do not check runout at all during normal reloading sessions. I think it was Erik Cortina that tested runout to 5 thousands and it had no measurable effect on accuracy. The video on it is on YouTube
 
Lock down.

Die alignment in press- The shell holder must contact the botton of the fl die first.
The tighten the die lock ring for alignment.

Redding competition bushing shell holder set allows the contact & control of shoulder bump.

Lee die? Not to my liking.
My 1970s Lee 223 die, could not push out crimped primers.

For me- Threaded decapper pin, made by RCBS, ty.
Im only talking about the lock ring that secures the de capping stem threads
 
Lock down.

Die alignment in press- The shell holder must contact the botton of the fl die first.
The tighten the die lock ring for alignment.

Redding competition bushing shell holder set allows the contact & control of shoulder bump.

Lee die? Not to my liking.
My 1970s Lee 223 die, could not push out crimped primers.

For me- Threaded decapper pin, made by RCBS, ty.
Its a Redding die
 
Im only talking about the lock ring that secures the de capping stem threads
Do you think the stem itself flexes enough that may not matter
as far as bending the neck with the seating stem/ball anyway
not a bad thought though you got there, any little amount of slop in the threads laterally may help
good to try it out.
You may be able to use an oring to simply snug up under the lock ring like a Lee die
---
as for runout, the biggest contributor I have found is neck tension resistance to the bullet being seated causing shoulder flex and spring back
---
let me put it this way
if you want your bullet seated at 3.000" and you now have it set to 2.998"
and you run your seating stem in by micrometer .002"
will it actually seat the bullet .002" deeper?
or will it simply push against the bullet, the neck tension not allowing seating any deeper,
the shoulder flexing
and when you remove the cartridge it is still at 2.998"
 
I use a Lee decapping die for that so I could remove the pin and never break anything.
I also like to use the Lee Universal die in a Lee press to help keep most of the dirty crap out of my expensive press. And that primer catcher system works pretty well. Just watch for bridging in the catch basin area.
 
Forster just had a good discussion on this. Personally, I like to use the Forster honed full length resizing dies with the expander ball up high as they have it designed. You could probably fast forward to the 7:50 time stamp to get at the discussion in hand.

 
All is not equal. If you are shooting custom rifles with custom tight-fitting chambers and you are turning your necks, maybe this works for you. If this works, then by all means keep doing it but, everyone is not involved in that kind of shooting. I believe that for everyone else, we should be using something to set the inside diameter as the final sizing step.
 
Well, I agree with you, I use a 3-step sizing process with new brass, will use the 308win for example, I start off with expanding the necks with a 307dia mandrel, if it's a gas gun I do not turn the necks, if it's 1 of my precision bolt guns I turn the necks I run the cases through a Sheriden slotted case gage to make sure the cases are in spec, next I trim and chamfer, prime and load! fired brass gets cleaned first with a wet tumble, body sized with a Redding body die after 3 firings for my bolt guns, neck sized with a LEE collet die annealed trimmed and chamfered primed and loaded, my gas guns with fired cases get wet tumbled body sized with a Redding SB die neck sized with a LCD, annealed trimmed chamfered primed and loaded, I also check the flash holes for size and uniformity, but usually after I firer my brass I only body size them and use a Lee Collet die to size the necks, my runout is 1k or less with this method, I use this method on both my gas guns and bolt guns YMMV.
 
Well, I agree with you, I use a 3-step sizing process with new brass, will use the 308win for example, I start off with expanding the necks with a 307dia mandrel, if it's a gas gun I do not turn the necks, if it's 1 of my precision bolt guns I turn the necks I run the cases through a Sheriden slotted case gage to make sure the cases are in spec, next I trim and chamfer, prime and load! fired brass gets cleaned first with a wet tumble, body sized with a Redding body die after 3 firings for my bolt guns, neck sized with a LEE collet die annealed trimmed and chamfered primed and loaded, my gas guns with fired cases get wet tumbled body sized with a Redding SB die neck sized with a LCD, annealed trimmed chamfered primed and loaded, I also check the flash holes for size and uniformity, but usually after I firer my brass I only body size them and use a Lee Collet die to size the necks, my runout is 1k or less with this method, I use this method on both my gas guns and bolt guns YMMV.
 
This mandrel thing has left me a bit confused.

Bushing dies have relieved the longitudinal stress caused by the expander
button.

Do mandrels also create longitudinal stress ?

I've learned to use the Lee collets with pin gauges (Class ZZ)
to get a wider choice of mandrel diameter and precision. I can't say this is an improvement over bushing dies but it has eliminated having so many bushings.

The use of bushing dies brings back the old warning----if it works, don't
mess with it. However, some also like the use of body and collet dies.

Whatever works !

A. Weldy
 

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