A High points primer for new guys.

[Harter66]

There ought to be a sticky that hits the basic high points of when to step form and when to just ram it home in a sizer,tips for fire forming like how to tell a correct AI from an almost right AI , beating Enfield stretch,what to do with a mystery wild cat that's almost common,forming in sloppy chambers,etc I'm actually suprised that someone hasn't created 1. Feel free to add to this as a 1 stop basics thread.

When to neck size only.
Neck sizing is just what it sounds like . It can be done as easily as backing the full length die out from 1/2 to 1 full turn or with neck specific neck sizing dies or even with a die of a larger cartridge case size but a correct neck diameter. As an example a 7x57 could be neck sized and even have part of the shoulder set back with a 7mm 08 die or a 280 Rem could use a 280 AI or 7mm mag die. Both of the latter could be done likely w/o a die adjustmentioned while the first would need to have the die backed out about a quarter of an inch.
I would say any time accuracy is the highest priority and Mr gun will tolerate it,or you have an oversized or maximum dimensions chamber.

What about step forming ?
Well it's done when you want to make a big case into a little 1. Like 22-250 from 30-06' as an extreme but common example. This is a bad example for me but I would take a 1st step to 8x57 then 308 then 300 Savage cut a half to 3/4 inch off the neck anneal and step to 250 Savage and finally to 22-250 ream and trim size ream fire form. There is of course a forming die set for this.

What about big sloppy chambers that shoot lousy and give back weird shaped cases . See neck sizing.
I have seen a couple of chambers that give back oval cases that will chamber back in any rotation and will eventually be centered . 1 trick here is to put an "0" ring on a rimmed case at the rim ,popular in 303 British for the Enfields . A lap of Scotch tape around the head/web area of the case will hold the case base centered or closer to center of the chamber. I've done this for 45 Colts and 7x6.8 Rem. There are several cartridges that are commonly formed from 06 and x57 that actually have a slightly different head dia that will take to this nicely . Arisaka and Swedes come to mind along with 220 Swift.

[Harter66]

I found a great use for my Lee 45 ACP fdc ,it is perfect as an over sized sizer for my Colts in the Rosschester . It leaves them at 482 with no coke bottle like the Carbide sizer decapper . I think my next project is a new decaping pin to fit the Lee die.

[EDG]

I will comment about neck sizing BOTTLE NECK cases.

First there is pure neck sizing using a purpose built neck sizing die in a press or a hand die or a bushing die of some sort.
No matter what you do you only size the neck and nothing else.

Then there is neck sizing attempted with a FL die. Sometimes it works OK. Sometimes not.

If you think you want to try neck sizing and you already have a FL die it costs nothing.
However it does not always work the way you expect.

When you have a case with a short neck - (think .243 or .300 Savage) and a body with little taper (think .243 again) you do not have a good combination for pure neck sizing.

Then there are the variations in the dies and the chambers that can add more variation to the process. More to follow.

1. When the neck is really short and the body has little taper the following occurs.
The case has to be forced into the die until the die almost touches the shoulder to get most of the neck. Since the case and the die has little taper the sizing of the body begins before the neck it touched. When the body is squeezed in, but before the shoulder hits the shoulder of the die, the case shoulder bulges forward. If you stop the process for neck sizing only you will have bulged the shoulder forward causing some cases to be hard to chamber even though you think you only sized the neck.
This bulging is reduced if your chamber is tight (fired brass is smaller) and the FL die is toward the large side of the die dimensions (Not as much body sizing). If your chamber is fat then the fired brass will be fatter too. If the sizer is tight and you have the fat brass from a larger chamber the shoulder bulging will accentuated.

For some rounds it works better to size with die designed for neck sizing or a FL die of a fatter round. If you do not have that other die and do not want to spend money on a neck sizing only die you can partial size. My first rounds loaded for a 6.5X53R Dutch Mannlicher used a trim die to form the case and left the neck .010 oversize. The neck was necked sized on the upper half using a 6.5X55 Swedish Mauser FL die. The skinnier Mannlicher case body was not touched by the 6.5X55 FL die.

For neck sizing with a FL die then:

A long neck with a lot of body taper is easier to manage. Think 7X57, .257 Roberts, 6mm Rem, .30-06, 270 Win, .220 Swift. Just size the upper half of the neck about 1 caliber down and call it done.

2. For the short necked , straight body modern wonders you should think about partial sizing with your FL die. Partial sizing is also good for the long necked variety too.
This process is much more precise if you have one of the Stoney Point/Hornady case gauge tools.
You can start out with the expander ball removed. You must start out with a case fired in your rifle for best understanding when you set the partial sizing up. You also need a positive lock ring on your loading die. The Lee rings are no good for this. You will be setting the die very precisely for your chamber. You also need a shell holder that will always stay with your die or you can use a shell holder of known depth. I have one shell holder for most of the .30-06 case heads that is exactly .125 deep. You should control the shell holder used since variations in shell holder depths will cause variations in headspace if you switch them later.
Check your brass to be partial sized with the Stoney Point tool. Then begin sizing. As you get close to the shoulder - say within .005 to .020 the shoulder will start moving forward up to about .002 or .003. Sometimes as little as .001. These bulged shoulders will be tight in your chamber. You can check one to verify the drag on the bolt when you lock the rifle.
Using the Stoney you can inch down the sizer by noting the rotation of the die OD with a witness mark on the die body and press frame. Use a Sharpie or equivalent. On my screen the " - " is about .040 long. If you mark the OD of the die body - (not the ring) the die body has to turn about .040 on its circumference to advance downward .001. Use this to sneak up on a setting that will permit the bolt to close with only a tiny bit of drag.
This length measured with your Stoney is the length of the chamber to the datum circle. Write this down and save it because it is a permanent dimension of your rifle. You can leave the die set at this dimension if you use it only at the range and it is a bolt gun. Hunting, match and other field ammo will normally need .001 to .002 clearance to insure function. I would set an autoloader, pump, lever gun and autoloader to about .002 clearance to insure function of these.
You have to keep your chamber and ammo clean because any grit or debris can prevent ammo that is this closely fitted from chambering. I think you will find your ammo will shoot better - more accurately with it set up like this.

3. Partial sizing as described is not without some issues that have to be addressed.
A. Because you are really doing a minimum sizing with a FL die you have to use case lube
B. Because your cases have almost NO clearance they cannot vary or they will not chamber. At this close tolerance of .000 to .002 clearance almost anything will cause some variation of the case body length.


The amount of lube - Too little lube, the friction goes up, the press stretches more & the case is longer
Sizing too fast and the case will be too long- too fast on the down stroke because you are in a hurry
No dwell at the top of the press stroke and the case will be too long - dwell about 3 to 4 seconds
Fat oversize swelled up cases from another rifle or military surplus machine gun rounds - harder to size and they will be too long
Hard cases will be longer
If you set up with hard or fat cases - when you size a soft case it may be too short


C. To cure all of these variations simply

Use the same amount of lube
Set up with your normal brass
Size the case slowly and delibrately
Let the press dwell at the top for about 3 to 4 seconds
This is the killer - retract the case just enough to spin it 120 degrees and size it slowly again with the dwell at the top. Retract and repeat for a 3rd sizing with the dwell.


If you measure your cases with the Stoney tool you can see the variations produced by variations in the sizing speed and technique. The multiple sizing passes get rid of that variation. Consistent sizing will produce each and every case with the same length to the shoulder. Your accuracy will be better and your brass will live longer. If you're sizing your brass with .000 to .001 clearance, and you do not use loads that expand the head, your brass will last a very long time. If you properly anneal your brass and size it in this manner - at least in a front locking bolt gun it may last 30 to 50 reloads.