Using FL sizing die without expander ball on fire formed brass...then seating bullet, is this ok?

[want2learn]

Hi, i was just thinking, i read in one of the posts that the expander ball in the FL sizing dies might not be the best way to expand the neck as it pulls up as opposed to a neck expander mandrel set up.

As such, wouldn't a fire formed case closely and concentrically match the chamber....and if so, then using a FL sizing die on a clean fire formed case should bring back to tolerance any neck/shoulder/body issues. At that point couldn't one just prime, fill and then use the bullet seating die? Do you really need a mandrel expander die or does the FL sizing die narrow the neck too much even without the expander ball?

it's the middle of the night and so can't test out this theory without waking everyone...but wondering if others have done this and if it's sound. thanks

 

[Ryridesmotox]

Unless you are using an appropriately sized bushing, your FL die will size the neck diameter down too small to put an appropriate bullet in.

 

[supercorndogs]

The neck is a standard FL die is way undersized vs the caliber it is for. If you want to works your necks separately in my opinion you should have a body die or a bushing die with the expander ball removed. I don't think pulling the expander from a standard die, is a good way to do it.

 

[spife7980]

The die is designed so that the thinnest necks (less over all material to take up space) will still be sized. That means for the vast majority of it all you will be sizing way too much. Most people like to have .002" of interference fit between the case and the bullet but most dies will size the necks down .010 and then open it back up. If you have thicker necks and get .010 youll have bullet issues due to shaving jackets, deforming bullets, inconsistencies etc.

Take the ball out and size a piece and see how much it sizes it for yourself.

 

[straightshooter1]

Hi, i was just thinking, i read in one of the posts that the expander ball in the FL sizing dies might not be the best way to expand the neck as it pulls up as opposed to a neck expander mandrel set up.

As such, wouldn't a fire formed case closely and concentrically match the chamber....and if so, then using a FL sizing die on a clean fire formed case should bring back to tolerance any neck/shoulder/body issues. At that point couldn't one just prime, fill and then use the bullet seating die? Do you really need a mandrel expander die or does the FL sizing die narrow the neck too much even without the expander ball?

it's the middle of the night and so can't test out this theory without waking everyone...but wondering if others have done this and if it's sound. thanks

First, it really comes down to just how much precision one wants or needs in their cartridge for the type of shooting being done. Then one should understand that the mass production process for brass induces various irregularities, one being variations in the thickness of the case from one side to the other. This particular variation, depending to what extent will result in variations in seating pressure and concentricity off the bullet, which effects shooting with accuracy/precision.

You're right, when a cases is fired formed and subsequently fired, it will concentrically match the chamber where the neck's axis is aligned with the case body axis. Then if a FL sizing die is rammed over the case, it too will have the same effect . . . and that being any of the case wall thickness irregularities being moved to the inside of the case. If the die is using an expander ball, in that die where on the those irregularities have been moved to the inside, the expander ball will now push against these irregularities against the wall of the die as it's drawn upward, which is what creates concentricity issues in the neck. Often it'll pull the neck's axis out of alignment with the case body's axis. And some expander balls are worse at it than others depending on it's design.

When using an expanding mandrel after the neck (or the whole case) has been sized down, the case wall thickness irregularities on the neck are move to the outside. The inside surface diameter of case neck will have formed to the mandrel (though there's always some spring back if not over annealed) leaving it very uniform and if the expander mandrel is used properly, one will have pretty good concentricity and the two axes will remain in alignment.

I've tested and measured and tested and measured again and again to be sure I understood what what happening with my brass and the above is what I found when sizing .308 brass.

 

[want2learn]

i really appreciate the information/help. thanks for taking the time.

what stimulated these thoughts was an transcribed interview with Froggy (famous bench rest shooter) in which he described his reloading technique/steps. I shortened the text to pertinent steps or stages. Here's the reference in case you're interested: https://www.accurateshooter.com/shooting-skills/bugholes-from-bipod/.

"1) I tumble the brass for a couple of hours to clean the necks up.
2) I then use a little Imperial sizing wax on a RCBS pad to lightly coat the neck area of the cases.
3)Full-Length Redding resizing die goes into the press. This die is adjusted to bump the shoulder exactly .001-.002″. I have removed the expander ball on the decapping shaft.
4)Now that all of my brass has been full-length resized and de-primed, I clean out the primer pockets
5)Next the brass goes back into my tumbler to clean off all of the residual wax.

6)I brush the I.D. of the necks with a bronze 30 caliber brush, then I use Froggy’s Neck Lube inside the necks, applied with a Q-tip.

7)I then prime all of my brass with a hand-priming tool.
8)Brass is charged.

9)Now it’s time to seat the bullets. I use Redding Competition Micrometer bullet seaters. "

 

[straightshooter1]

i really appreciate the information/help. thanks for taking the time.

what stimulated these thoughts was an transcribed interview with Froggy (famous bench rest shooter) in which he described his reloading technique/steps. I shortened the text to pertinent steps or stages. Here's the reference in case you're interested: https://www.accurateshooter.com/shooting-skills/bugholes-from-bipod/.

"1) I tumble the brass for a couple of hours to clean the necks up.
2) I then use a little Imperial sizing wax on a RCBS pad to lightly coat the neck area of the cases.
3)Full-Length Redding resizing die goes into the press. This die is adjusted to bump the shoulder exactly .001-.002″. I have removed the expander ball on the decapping shaft.
4)Now that all of my brass has been full-length resized and de-primed, I clean out the primer pockets
5)Next the brass goes back into my tumbler to clean off all of the residual wax.

6)I brush the I.D. of the necks with a bronze 30 caliber brush, then I use Froggy’s Neck Lube inside the necks, applied with a Q-tip.

7)I then prime all of my brass with a hand-priming tool.
8)Brass is charged.

9)Now it’s time to seat the bullets. I use Redding Competition Micrometer bullet seaters. "

Sounds very similar to my routine (though, I do anneal after every firing) . . . AFTER I have tuned my cases. And I think that's what's missing there, in that it doesn't really seem to be addressing any of the initial tuning of the case, only the routine afterwards. But his description of his "routine" does give some insight, which is certainly helpful.