Do I have a sizing die issue?

[Brians356]

So it's a custom FL die matching the chamber, yet it's a bushing die? That seems almost antithetical.

But if the .002 runout you measure is relative to the body, it can't be misalignment of the die to the shell holder. It almost has to be the neck bushing orofice is not coaxial with the die body, which is hard to imagine.

If the necks are not of uniform thickness, runout measurements are of dubious value, in any event, seems to me.

 

[Dusty Stevens]

Most every custom die made for the gun is a FL bushing die. Most are made from newlon blanks

 

[Brians356]

Most every custom die made for the gun is a FL bushing die. Most are made from newlon blanks

Well I'll be dipped.

 

[BoydAllen]

Some years back, knew a fellow who had designed a chamber reamer to produce a tight neck chamber that was a perfect match to an ordinary one piece FL die. He came up with the body dimensions by sizing well used cases and specifying his reamer body dimensions to give the loaded round chamber clearance that he wanted in that area, and calculated his chamber neck diameter so that his loaded round clearance and neck tension were what he wanted. Of course this required measuring brass sized with the die, without the expander. The result was extremely straight sized brass, that had the correct neck tension, and the clearances that he wanted for both body and neck. Some time later, at my suggestion, a friend ordered a custom one piece Fl die configured so that there was .001 difference in neck tension between case necks sized with and without the expander. Since the "work" the expander was doing was so little, it had no effect on case straightness. I mention all of this just to let readers know that there are other options.

 

[Brians356]

For a truly tight-neck chamber (< .001 total clearance) I don't see how anything but a simple one-piece FL die would be satisfactory. But I will ponder some more ...

 

[BoydAllen]

For me, and a lot of others tight neck is anything that requires turning. What you describe is the old school method that does not see much use these days, where the clearance is less than the elastic limit of brass, so that it snaps back, and does not require sizing to hold a bullet. I call that a fitted neck. One that is purely my own, that I always try to remember explain is what I call a close neck, which is a no turn that is calculated to have less clearance than any factory chamber.

 

[Patch700]

For a truly tight-neck chamber (< .001 total clearance) I don't see how anything but a simple one-piece FL die would be satisfactory. But I will ponder some more ...

You are referring to a fitted neck... And that did not need a die of any kind except to knock out primers and one to seat bullets..

I have tight neck chamberings that have .004" clearance on a loaded round .

In the words of F. Guffey "This was even before the internet"

 

[Brians356]

For a truly tight-neck chamber (< .001 total clearance) I don't see how anything but a simple one-piece FL die would be satisfactory. But I will ponder some more ...

You are referring to a fitted neck..

No, you are referring to a fitted neck.

A fitted neck is indeed a truly tight neck (can there be one any tighter?), but a tight neck is not necessarily a fitted neck. But back to the issue I raised: Can a neck w/ < .001 clearance (by whatever name) be serviced with a bushing die?

 

[Dusty Stevens]

Where did the fitted neck even come from? James had a custom FL die made- which would be a bushing die these days made to fit his chamber. The die evidently has some runout. Shouldnt have any but its working about like a factory fl bushing die runout-wise

 

[Dusty Stevens]

And yes if he was to use a bushing die on a fitted neck he could choose a bushing, get a carbide one in half thou or custom hone a bushing for whatever size his particular necks are. No different than any other ctg except the clearances are dangerously close