Home Forums Hunting & Shooting Ask The Gunwriters Neck Sizing vs FL Sizing

I only use Forster dies now.Run out is almost non existent using the Fl or NS and their seating dies are superior to all but custom made dies.

I have definitely had 7 mm RM and .300 Win Mag cases that would not load after neck resizing only. I used a FL sizing die to set the shoulder back .004 inch and in each case then they chambered -- but with more effort than new ammo. I admit I did not try to put these cases back in the chamber after firing. I'll do that next time.

So you are saying there is something wrong with my neck-sizing technique? What would that be?

Also, someone said to partial FL size to run the die down to the shell holder and then back off, I don't believe that will work. You have to run the die about one turn past contact and THEN back off some. But you need some device to measure how much you are setting the shoulder back.

Nothing wrong with your neck sizing technique--ol' Dan_Oz is omitting the fact some brass doesn't spring back as much and all brass loses a tiny bit of it's elasticity every time we fire it.

Rarely will PFLR brass not chamber into the same rifle it was fired in. You want to bump the shoulder back .001-.002, and that will determine how far to screw the die down. I use Hornady/Stoney Point headspace gauge.

https://www.hornady.com/reloading/precision-measuring/precision-tools-and-gauges/headspace-comparator-anvil-base-kit#!/

In your case with belted magnums sometimes right above the belt isn't sized enough, especially after multiple firings. There is a die made to address that but cannot remember who makes it. Maybe somebody else can chime in.

Of course, I'm' assuming you're using a neck die to size the neck rather than attempting it with a FL die.

Yes, I was using neck sizing dies, and since PFL sizing fixed the problem, the problem wasn't because of expansion ahead of the belt. Sinclair makes that die you are talking about.

Do you see what I see ? (set to music)

In 40 PLUS years I've never had the problems mentioned in this thread.
P F L sizing works - if you know how to use it !

"It's easy to make loading hunting rounds hard "
We can OVERthink it pretty easily.

Jerry

I'm not saying that you are doing something wrong, but there might be things you could do differently ;-)

The case, when you extracted it, fit the chamber. It simply can't be bigger than the chamber it just came out of, so if it won't go back in after you've reloaded it then it is a matter of understanding why. Among the likely causes, assuming it isn't a problem with the chamber, is the process used to reload. For example if the die you are using is one with an expander ball, pulled back through the neck as it comes out of the sizing die, then drag from that ball may well pull the neck forward, in turn moving the shoulder. Another possibility is if you are partially sizing with a FL die, but have it adjusted far enough that the part of the die meant for the sides of the case is coming into contact with the case, without the part meant for the shoulder itself coming into contact, thereby squeezing the shoulder forward slightly.

There can be other causes too, and I've mentioned a couple of them earlier in this thread.

It is entirely up to you though. I'm just describing what I've found, and what works for me.

I omitted saying that because it is arrant nonsense. I covered this earlier in the thread.

But it's not arrant nonsense any metal including brass work hardens. And it doesn't matter if we squeeze it a lot with a die and lose a lot of elasticity or expand it a little with chamber pressure and lose a tiny amount each time.

I understand the difference between ductility and elasticity.

Although you may be correct a neck die can potentially pull the neck forward--which is why I lube the necks of my brass even when the neck die doesn't call for it. It's easy enough to measure if that happens with my Stony Point gauge.

Tag

Work hardening doesn't "reduce elasticity" That is indeed arrant nonsense. It increases the yield stress, so you might actually say, in layman's terms, it increases the elasticity, in the sense that the stress range over which elastic behaviour is seen is increased, but the modulus of elasticity is unchanged, so you get more elastic strain before yielding. It also tends to decrease ductility




I suspect that you don't.

Oh, and not all metals can be work hardened either.

Casey, what do you exactly mean by "losing" elasticity? I guess in 30+ years in the materials testing arena and having tested all sorts of engineering alloys, I'm curious to what you mean by "lose". I gather that Dan has a materials background and understands strain hardening, strain softening, elastic-perfectly plastic, Ramberg-Osgood, elastic unloading, consumed ductility, etc. and this may be his refined understanding of material mechanics.

Elasticity is the Hookean response of the material..ie the linear stress-strain response. To say a material "loses" that means it's modulus changes over strain cycling; which is absolutely not tne case for cartridge brass or a wide range of engineering alloys. Its proportional limit/yield strength (increases for strain hardening materials) will change assuming plasticity is reached and ductility is consumed. Subsequent plastic strain cycles will have a new characteristic stress-strain response if plasticity has been reached during previous cycles but its elasticity (linear response) will not change or be lost. The unloading stifness would clearly show that.

JF

No one else saw what you saw Jerry because you didn't see what you think. I had problems neck sizing. PFL sizing FIXED the problem. I have never had problems with PFL sizing.

I was wrong about who makes that dies. Larry Willis of Innovative Technologies makes it.


Innovative Technologies

Dan_Oz - so you admit that there can be a problem with regular neck sizing dies possibly pulling the shoulder forward. That seems to me a good reason why I might have had a problem EXCEPT I was using the Lee collet die on the 300 WM. Anyway, I am going to stick with PFL -- it works.

You obviously know a lot about metallurgy but gun writers have been talking about cases losing elasticity for as long as I can remember, so please excuse us for repeating things that so-called experts have written.

Regardless of whether it is reduced elasticity or ductility or something else, do cases become less likely to snap back into position after repeated firings?

without reading the entire thread...

neck size always... if the shoulder needs bumping back,
I use a body die for that....

or just a larger caliber with the spindle removed..
eg: a 260 without the spindle makes a perfect body die for 243..

anneal necks every 4th shooting...

don't go for max velocity most of the time, so that reduces
pressure and doesn't require the brass to worked as hard to
resize....

this gives me pretty accurate ammo, and also great brass life...

40-50 reloads or more...

I did not know that but it makes sense. Will definitely be giving that a try 😀


Trystan

Then I'm glad to know we will never have to anneal the necks of our brass again.........

JF,

Each time our brass is worked--in a die or in the chamber of our firearms--it loses a certain amount of it's ability to springback. That's elasticity as it applies to our brass.

Essentially oz is suggesting we will never have to do anything but neck size brass regardless if we shoot it a bazillion times. I'm not aware of anybody demonstrating that, and given handloaders willingness to tinker it should have been demonstrated a long time ago--if it was true.

Thanks for reminding who makes those dies.

I saw your PFLR because I use it about half the time. I'm mostly interested in making lightweight hunting rifles as accurate as a I can, and to that end concentricity is the goal. I don't care how I get there whether NK sizing or PFLR. And like others I want my rounds to chamber easily and quickly because a fast follow-up shot is always a possibility--especially when jump shooting elk in the timber........

Can you tell us exactly how a Lee collet neck sizing die can yank the shoulders forward during use?