inconsistent neck sizing 338 Lapua using redding dies & Forster Co-Ax press

[jkuengineer]

so i'm having a head scratching moment. i asked my local reloading store for advise and they said i'm doing everything correct. advised me to call redding they said the same thing.. not sure whats happening exactly here.

i have a co-ax press using the redding deluxe dies (not the competition bushing set). using S&B brass once fired. i have a set of brand new lapua brass but wanted to learn on this first.

so, i take out the primers using a primer die then tumble in walnut then cob. then i lube the cases and the necks (lyman spray on outsides and graphite dip inside the necks). then i put the full lenght sizing die in the press and adjust to where i get .002 neck push back with the case. the neck does get pushed down and resized every time i try to adjust but was told thats not a problem. so i get my die set correctly and lock in the nut. second case comes out ok. third case, pushed back .005... ok? two other cases come out ok then last case grew .005... i have no idea whats happening here.

then was told to only neck size by the redding rep to see if anything changes, which he told me also pushes the shoulder back as well just doesn't size the case down all the way. same thing im getting inconsistent results.

any idea what i may be doing wrong? i do have experience reloading 30-06 and other rounds but have never had this issue. i know this case is different but im pretty good at this stuff but this is a real head scratcher for me.

i know im doing something wrong. any advice is really appreciated. i tried hornady brass as well. same thing.

[jkuengineer]

for the measurements i have the RCBS 338 LM micrometer which measures your offset from the SAAMI specs my rifle chamber seems to be .001 larger then the minimum SAAMI numbers.

the cases that grew 4-6thou, is it ok to lube again and just size it again? i know the expander ball has some tightness when going through the neck again but was told its not an issue.

[J-cat]

Try Imperial sizing wax, and if that doesn’t help, convert the press to shell holders and get a Redding competition set, then adjust the die to hard stop on the shell holders during sizing.

[jkuengineer]

[J-cat]

The press flexes under pressure so the lube friction variable combined with the press flex causes shoulder bump inconsistency. The only way to eliminate it is to adjust the die to hard stop against the shell holder. The problem with that method is you’ll be bumping the shoulder too much with most dies. Hence the competition shell holders. They have incrementally taller deck heights for precise shoulder bump.

[divingin]

I suspect the same as JCat. Inconsistent lube causing inconsistent press stretch, resulting in inconsistent sizing.

One thing that may make your setup easier is to temporarily remove the decapping pin and expander. Set the die up so you get the right amount of bump, then reinstall the decapper/expander and recheck. Pushing and pulling the expander through can do weird things.

If you can reach the shoulder setback with what you're using now, I doubt going to a regular shellholder will get you much (though the hard stop would tell you when you've got the setup right, though the lock rings are supposed to do that as well.)

As an aside; I've never seen a dry tumbler do much to the primer pockets in terms of cleaning. If it were me, I'd lose the decap step before tumbling, and if I were worried about the pockets, use a pocket cleaner as a separate step.

[baih777]

Try annealing 5 cases and see if that helps.

[fguffey]

any idea what i may be doing wrong?

Yes; I do not believe you have talked to one person that has a clue as to what happens when the case is sized. That include neck sizing. Reloaders believe they have the ability to move the shoulder back, some believe they are so good at it they can bump it back.

It is impossible to bump and or move the shoulder back with a die that has full case body support. I have moved shoulders back, when finished the case took on the appearance of a Volkswagen thermostat with bellows.

F. Guffey

[fguffey]

The press flexes under pressure so the lube friction variable combined with the press flex causes shoulder bump inconsistency

Just how difficult is it to neck size a case? How tough are those cases?

A reloader should be able to determine If the case was full length sized before lowering the handle, And then there is flex; why can't a reloader determine the amount of flex. When I size a case I want to know if the case won or the press won.

F. Guffey

[kcstott]

Yes; I do not believe you have talked to one person that has a clue as to what happens when the case is sized. That include neck sizing. Reloaders believe they have the ability to move the shoulder back, some believe they are so good at it they can bump it back.

It is impossible to bump and or move the shoulder back with a die that has full case body support. I have moved shoulders back, when finished the case took on the appearance of a Volkswagen thermostat with bellows.

F. Guffey

Guffey
you are full of crap. and you know it.

I have two dies that have no issue pushing the shoulder back. Yes I measure the case before and after sizing and the shoulder does move.
one die is the Forster bushing bump die, the other is David Tubb's 6xc bushing small base sizer. Both can push the shoulder back .010" if you desire on fire formed brass.

I'm so damn sick and tired of you blathering on and on that you are the only one that knows anything. You're nothing but a self centered narcissistic idiot.

I've called you out multiple times, I'm calling you out again. Put up or shut up. Demonstrate how it's done or STFU and move on.

[jkuengineer]

I suspect the same as JCat. Inconsistent lube causing inconsistent press stretch, resulting in inconsistent sizing.

One thing that may make your setup easier is to temporarily remove the decapping pin and expander. Set the die up so you get the right amount of bump, then reinstall the decapper/expander and recheck. Pushing and pulling the expander through can do weird things.

If you can reach the shoulder setback with what you're using now, I doubt going to a regular shellholder will get you much (though the hard stop would tell you when you've got the setup right, though the lock rings are supposed to do that as well.)

As an aside; I've never seen a dry tumbler do much to the primer pockets in terms of cleaning. If it were me, I'd lose the decap step before tumbling, and if I were worried about the pockets, use a pocket cleaner as a separate step.

[jkuengineer]

Try annealing 5 cases and see if that helps.

[ar15barrels]

So i took out the expanded ball and set the shoulder bump i got fairly consistent numbers.
I put the expanded ball in and everything goes weird from 1 out of every 4.

Your expander button is pulling the shoulder forward.
Get an expander mandrel in a separate die so you are expanding on the down stroke instead of the upstroke or have your die's neck diameter honed out some to get a closer match to what your brass needs so that there will not be so much tension when the button pulls back through the neck.

How much difference in neck diameter do you see on cases sized without the expander button vs the cases sized with the neck expander button in place?

[J-cat]

That, or get a bushing die and don’t size the neck so much. Or get a Forster die with the neck honed out to match your brass.

[ar15barrels]

I can hone the neck on any brand of die to get it to the desired diameter.