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

It isn’t a matter of admitting anything, it is what I have said from the start:





Well in that case I’d be looking for another cause. I haven’t experienced that problem with Lee Collet dies, and can’t see how it would occur as a result of using them, but there may have been some other issue at play. There are several possibilities I can think of, and I have little doubt there are others I haven’t thought of too.



And if it works for you, then stay with it. As I’ve said, I have simply outlined what works for me, and why.



As I said earlier:




Elasticity and ductility are two different things, and I think that confusing the two is part of the problem people have with this stuff.



Perhaps I can illustrate it with the above, which is a sort of simplified example of what happens as we apply stress to a metal like cartridge brass. I have taken the diagram from Wikipedia, which actually has a pretty good and simple explanation of this.

What you have in the area between 1 and 2 is elastic behaviour. The strain (ie deformation of the material) is proportional to the applied stress, obeying Hooke’s law. The gradient of the slope is a the modulus of elasticity, aka Young’s modulus, a measure of stiffness. If you release the stress before reaching point 2, the piece will return to its original dimensions. That is elastic behaviour. If there’s no stress raisers or defects you could do this over and over again, and the result will be the same. The item does not “lose elasticity”. That fact is what makes springs work.

Now if instead you continue to apply stress past point 2, the metal starts to undergo permanent (plastic) deformation. In the case of brass this is typically fairly obvious when you are testing it. You reach what is usually called the “yield stress” or “proportional limit”: stress is no longer proportional to strain. If you take it up to point 3, then release the stress, it will recover the elastic portion of the deformation, returning down the dotted orange line shown.

As you can see, this line is parallel to the line from 1 to 2. This means that modulus of elasticity is the same. This is called “elastic recovery. In other words, the elastic part of the defomation is fully recovered, and the permanent deformation is only that part left over, that part attributable to the strain incurred past the yield. and if you take that piece and stress it again to a level less than 3, it will still recover down that dotted orange line, over and over. You’ll also note now that you can stress it to a higher level than you could originally, without it yielding. That is because of the work hardening it has undergone.

Does that help?

You are still going to have to anneal case necks, even with neck sizing only. Of course the more cold working you do the more often you'll need to do it. Go back to my first post in this thread, and you'll see I mentioned it. Perhaps you missed that?

It doesn't matter how often you say it, it is still arrant nonsense.



What is a "bazillion"?

I stopped counting after about 30-odd loading cycles on a number of batches of brass, which had only ever been neck sized, never full length. Eventually you'll probably lose cases in the field, or leave it too long before annealing and split them, or have primer pockets get a bit big from pushing pressures or simply from wear (i have had pistol brass that went so many cycles that the headstamps became hard to read, and the primer pockets on some of those were pretty loose in the end).

As for people demonstrating this a long time ago, there in fact have been such demonstrations, since long before either of us was born. Reloading has been around since the first reloadable cases, not long after centrefire designs came out, and if you look at old reloading gear it is, more often than not, designed only to neck size. Any number of tong tools and straightline tools and Lee kits and our own Simplex presses here are witness to the fact that neck sizing was the norm.

This is epic. Giants of the industry.

No one said there'd be math.

I think what Dan is saying (without looking at that graph) is that if you don't load too hot then you need never do anything but neck size. Perhaps he said that many pages previous.

JGRaider - (BTW, I deer hunted this season with a fellow who says he knows you, named Buzz). I am not claiming that collet neck sizing dies pull the shoulder forward. I'm just claiming that I couldn't rechamber some brass after neck sizing and that PFL sizing fixed it so that I could.

And still trim when needed, I assume?

BTW, for the most part this has been one of the best threads in quite a while.

RM

And anneal cases!

Huntnshoot basically made the same statement without an explanation as Dan Oz was trying to explain . He necksizes annealing every 4 times or so and never has to push the shoulder back.

My thoughts were that the annealing process is allowing the case to then spring back after it is fired creating a bit more room that you otherwise run out of before the annealing process?!?!

I don't know but after annealing my next batch of brass I'm going to skip pushing the shoulder back and see what happens 😀



Trystan