Home Forums Hunting & Shooting Ask The Gunwriters Sizing unfired brass

Maybe this has been asked before but I was just wondering if anyone sizes unfired brass before they use it. I never have but other reloaders tell me they do. To me it seens like a waste of time but they say it makes sure the necks are straight and round.

Always....not adverse to cleaning up the necks and doing the flash holes and primer pockets as well.

Never...unless the case necks are beat up, then i may run them over the expander. boattails will iron out some pretty good dents though

Not adverse.........averse.

Word police gotta love em............I do size new brass to clean up the neck.

Correct...I typed that whilst serving a customer, please consider me suitably chastised.

Always size brass, one less variable in the precision train.

I go with the advice of my betters who are indeed the gunwriters and who have written books and appeared in videos addressing this exact subject.

That is I typically run a carbide expander ball through the neck - carbide to avoid lubrication - or a Lyman Type M die or a neck turning mandrill or what ever seems best at the time for the particular lot of cases - which can differ with the make of case and the packaging and the handling before I got them. That is current production Lapua, old production (packaging) Lapua and bulk packaged range scrap just might get different treatment.

On the other hand believing as I do that resizing changes the brass I'm dubious that my changes improve on the maker's factory efforts

that and avoiding unnecessary work hardening (and unnecessary work) are my thoughts also.

There's no reason to resize factory-new brass, except for straightening out and uniforming the diameter of the inside of the inside of the neck. That can be accomplished, as Clark noted, by running the neck over an expander ball. (I will note that new brass is prettyt slick, so there's no need for a carbide expander ball on new necks--though it definitely helps with fired brass.)

There are two possible negatives to sizing new brass:

1) If you adjust a full-length sizing die the way most instructiuons suggest, by screwing the die down until it firmly contacts the shell-holder, the cases may end up slightly short. This causes stretching and possible head separations. Many people who've contacted me, asking why they're getting head separations in 2-3 firings of new brass turn out to have been full-length sizing it before the first firing.

2) The standard full-length sizing die with an expander ball is fairly likely to pull the neck of the case out of alignment with the body. New brass is almost always VERY straight, because there's no expander ball involved in the final forming. So all you're doing is making the brass less straight.

If you want to demonstrate why new factory brass is straight, take the expander ball assembly out of your full-length die. Size a fired case, then measure the neck run-out. With rare exceptions, the neck straightness will be within .001" of the case body. This is EXACTLY how the final forming of factory brass is fone.

Now, put the expander ball assembly back in the die, and resize the same case. About 90% of the time neck will almost always not be as straight as it was before, and sometimes will quite crooked, as much as .005" out of round with the body.

This is why a lot of handloaders use bushing or collet dies WITHOUT expander balls. But even bushing or collet dies don't improve on the straightness of new brass. They won't hurt new brass, but they won't help it either. Which is why full-length resizing new brass is a waste of time.

All of which is exactly why I only run the neck over an expander ball, instead of running the entire case into a full-length die.

I usually only run an expander to true up the mouth and neck,chamfer and that's it..

I "resize" to get out the dents, there's no actual resizing going on.

I do trim and chamfer to get the whole lot to the same starting point. I've noticed overall length differences in brass out of the same bag and length is pretty close to maximum. Well past my usual trim-to length usually. Or maybe I'm just lucky buying brass.

I've even seen new brass length beyond SAAMI maximum. But the subject of this thread was sizing unfired brass, not trimming.
They're separate subjects.

One thing I have noticed over the years is that many handloaders like to spend time on procedures that make absolutely no difference--though most of them don't have the potential to create problems, like resizing new brass.

Mea culpa. I didn't recall length being addressed when prepping new brass so I meant to spark the thought.

So Mule Deer, if the expander ball likely if not obviously violates the Handloader's Hippocratic Oath why use it at all?? If the hole in the neck is large enough to accept the bullet base why not just let the bullet be the expander?? At least for fired brass.

I'm not answering for MD, but I don't want my bullets subjected to more than a .003" interference fit when I seat them. Depending on the particular brass and dies being used, a non-expanded neck may provide a lot more interference than that.

My case prep for bottleneck rifle cases includes sizing and checking for proper length (trimming if necessary) whether the case is new or has been fired several times.

Because case necks of fired brass are larger than the bullet they're going to hold.

I'm not averse to adverse comments.

Depends on the brass, Lapua, RWS, or Norma is well packed and the necks are normally straight. Remington, Federal, Winchester in the bulk pack are normally dented up some. These get run to straighten up the necks, not really sizing.