OzFclass

up until now, I have been a firm believer in the fact that FLSizing is a sure fire guarantee the get minimal runout in loaded ammo.
my new 6.5 super lr ammo has had consistent runout where the ogive meets the shank of up to 0.007, a thing I thought would go away with fireforming.
when it didn't, further investigation revealed zero to 0.001 runout on fired necks, and 0.004 on sized necks. holy shimoly the fls die was introducing runout
while I am not overly worried by runout, I would of course prefer to have none.
this might be why that barrel likes 0.020 jam. It tends to straighten things up.
ain't it a pita when a longfound theory goes down the gurgler
keep safe,
bruce.

What sort of die - threaded or Arbor?

If it's the former, it might be interesting to spot mark the base of the cases at the centre of the cutout on the shell holder to see whether there's a relationship to that. If the runout is consistently away from that point, you might have an issue with your die.

In the case of the latter, it could point to an out of concentric die if you marked a point on the case corresponding to a position on the die.

Of course, you could just be a crap assembler.

I had a "bent" FL die once and used workaround - I size 3 times rotating 120 deg in between. Reduced the runout dramatically. I do it automatically now with any FL die.

Bruce have you tried removing the decapping stem/expander and checking runout before expansion

john,first thing to check is always me.
pretty sure I am driving it right.
the best fls die I have was made by gilesy, and most ammo is less than 0.001 runout with worst being 0.0015.
we're talking threaded here.
your idea of marking the cases is a good one.
alan
I think I have what you had. what a pain having to do that.
dave,
this is happening without expanding, and with turned cases.
I strongly suspect that the seat for the bushing is crooked as alans crooked die.
what points to this is that max runout is achieved with the bushing tight, and there is a little less with the bushing loose in its housing.
unless maybe the hole in the bushing is not in line.
keep safe,
bruce.

Ooohh- it a FL bushing die - much different.
How much are they being sized?? (e.g. 294-290??)

dave,
295 to a bit less than 290.
that is after annealing.
they possibly would not go quite that small if not annealed due to springback.
the annealing is not affecting the runout, and is machine done, so consistency is reasonable.
keep safe,
bruce.

G'day Bruce,

I'm not suggesting a fix, just chasing a better understanding of the problem.

When you say they are not expanded, does that mean you have removed the expander ball from the die or does the die not have an expander ball.

Do you free float your dies in the press when sizing?

hi denis,
the expander is just too small to contact the inside of the neck. If I use a 0.001 smaller bushing, it will contact.
my die is adjusted down until it contacts a redding shell holder prior to the handle being fully depressed.
by fiddling with the ram a bit, I am assuming the die is roughly centred in the threads, and then lock the lockring down to hold it that way.
what this die is doing is taking cases with next to no runout and giving them heaps, suggesting that there is a bit lacking in its machining. i.e. the axis of the bushing housing in in a different alignment than the axis of the body. or the actual bushing is machined out of alignment.
the necks are being misaligned with the bodies of the cases.
keep safe,
bruce.

Bruce,

Maybe try a Lee lock ring. I'm pretty well convinced that they assist in aligning dies better than split or grub screw locked rings do.

John

Not saying this is your problem Bruce, but here's a similar situation I had and the advice I got at the time................ common knowledge in these circles I'm sure.

Years ago when I started reloading .308, I was using a Lyman Crusher press with Redding FLS Type S bushing dies and I was getting poor neck concentricity. I wrang Stuart at BRT ready to drop a wad of cash on a Forster Co-axe. He made three suggestions. First that I remove the expander ball, but that is ideally done in conjunction with neck turning for obvious reasons and then secondly to free float the dies. That is to set the die up for a .001" shoulder bump there abouts and then just back the die off a bee's dick (literally) so that the lock ring is still touching the press' die flange but you can ever so slightly jiggle it in the threads side to side.
The third was to free float the bush, but with that style of die, thats a given if your only trying to achieve 2/3 sizing of the neck length.

The difference in neck run out was immediately incredible. Down to .00075" +/- .00075" from the previous results of anywhere up to .006".
All results were using extremely concentric fireformed brass, < .0005"

Naturally I thought if I could get that with the Lyman, I could get better with a Forster Co-Axe.. Last year I bought a Forster and as lovely as it is to use, I haven't been able to improve on the Lyman's results and still mostly use the Lyman.

I see a lot of F-class shooters are using inline dies and arbour press' now. I suspect it would be extremely slow, but maybe someone that uses them could fill me in?

Bruce,
If you are sizing down 5 thou and creating 7 thou runout then it certainly sounds like something out of alignment.

I imagine you have also tried all the standard deals, backing off the bushing for free floating, other bushings etc.

A while ago I spent a great deal of time grinding the bushings to make for better alignment. When sizing down 4+ thou there becomes more room for the bushings to get out of line - I ground everything from slight tapers (worked very well) to specifically designed steps (e.g. in your case - half a neck at .295 for support then other half at .290) which would size half the neck in almost perfect alignment - if you wanted the full neck sized I had to run them again but flip the bushing which would then start off with half the neck aligned in the 290 and continue down.

Whilst all this works well the main die bushing recess must not impinge on the bushing at all (free floating) so if it is out of alignment then it is time for a new die. - Most die manufacturers will replace under warranty. - Also check the bottom of the decapping assembly where it contacts the bush does not have a lump on one side!

thanks guys.
bruce.