I've order an ONT for my Forster trimmer. I have some once fired Lapua .223 match brass. Should I neck size the cases before turning? I am considering a partial neck size to help stabilize the round in the chamber.

If I do, how much of the neck do you size with a Forster busing die?

So much to learn so little time!

Thanks once again, for your wisdom!

The neck turners I am aware of want you to use their "expander". It is sized to coordinate with the neck turner mandrel.
Not sure about the Forester unit. Most important for a good result is close tolerance fit of the brass neck on the turner mandrel. Too lose or too tight gives inconsistent cutting.
It helps to lube the mandrel just a little. I use Imperial sizing die wax.
You want to turn the neck all the way to the shoulder. This is a fine point here. If you don't cut up to the neck shoulder junction you create a doughnut. If you cut too far you can weaken the shoulder neck junction. I find for me that the cutter just kissing the shoulder is the right amount.

muck

Hey Rusty

muck is right that the inside diameter of the neck needs to be tight to the turning mandrel. I have the Forster hand held outside neck turner and just neck size with a Lee Collet and that is just right. It is tight and I have to rotate the hand turner as I push to get the mandrel in. If you have a regular neck sizer then those expander balls are usually too tight to get the mandrel in.

Sounds like you have the bench mounted manual trimmer that you are going to put the ONT on not the hand held like I have


I always turn on new cases but opinions vary and always turn a little into the neck


If you want to partial neck size


then you will have to do that after ONT and when resizing. It would not be a good idea to ONT only part of the neck IMO.

As the illustration immediately above shows, any effort to "partially" neck size would leave two diameters to the neck, a disaster to neck turning.

(Good photos, andI love my Forster HOT-100 turner too!)

Did you measure your neck thickness? Are you turning because it's uneven? Do you have a tight-necked chamber?

The reason that I ask is that I have gone through 1000s of Lapua cases and they didn't need to be turned.

I have ordered the neck trimming arbor for the Forster trimmerin addition to the ONT for the Forster trimmer.

Kelbro,
I am turning the necks to hopefully provide uniform pressure on the bullet.

Woods,
Thank you for including pictures of your setup and the results.

FWIW,

I only outside neck turn cases that will be shot in "Tight Neck" rifle chambers.

Don

quote:

Originally posted by Rusty:
I have ordered the neck trimming arbor for the Forster trimmerin addition to the ONT for the Forster trimmer.

Kelbro,
I am turning the necks to hopefully provide uniform pressure on the bullet.

Woods,
Thank you for including pictures of your setup and the results.

Rusty, my point was that Lapua brass seldom needs turning. It is some of the most consistent brass out there. You will have uniform pressure if the case walls/necks are of uniform thickness. If you do not measure first, you will be removing good brass for no reason. If you insist on turning just for the sake of turning, after you chuck it up and start to 'clean it up', you will see what I'm talking about.

If you don't have a tight-necked chamber, your goal in turning is to get brass as consistent as most Lapua is out of the box.

Have you pulled some measurements on that Lapua match brass?? Unless you have a custom cut chamber that needs the brass cut to fit, I think you'll find the lapua brass doesn't need turning.

The problem with Lapua brass is that it does not come in most common calibers

338 Lapua
9.3x62
7.62x54
7.62x39
30-06 (yeah, I have that one)
308
6.5x284
6.5x55
6.5x47
6.5 grendel
243
6mm BR
223 rem
222
220 russian
20 tactical

No 270, 280, 7 mag, 300 win mag, 338 win mag - not to mention the obscure calibers I have like the 6.5 rem mag, 338 RUM or 375 ruger.

So Lapua may be great brass although expensive, but it's not available for most of my reloading.

My understanding from the bench rest guys is to get uniform thickness. This then would give more uniform pressure on the bullet and hence better accuracy. I doubt it would make make much difference in my shooting. These guys swear it tightens up their groups.

What a coincidence, I just turned the necks on 100 22.250 Winchester cases tonight.

Sized to an inside neck diameter of .224" the outside neck thicknesses varied from .249" up to .253" and my chamber was cut to .250".

I just turned them all to .248".

One problem is that if you have a piece of brass that has a large variance to begin with, then outside neck turning will not make the neck concentric with the case body


that's why sorting brass by neck thickness variation to begin with is a good idea.

Agreed ; I Learned that from Woods !. I thank You again for your keen in site on making PRETTY as well as ACCURATE AMMO !. X2

If the ONT for your Forster trimmer is like the Lyman, you will need to FLRS first. It should come with instructions. Sizing 1/2 of the neck works well for me in 243win. But your working with 223. There is a wide range of chambers and neck wall thickness of the brass. Neck turning may do more harm than good. Test with bushing dies first before neck turning. Then try some turned and compare."NOTE: The Forster Outside Neck Turner is designed to be used after the neck has been resized and expanded." Forster

If you are determined to follow thru with the neck turning, I would suggest that you fire form your brass and then FLRS it. And then neck turn it ALL THE WAY TO THE SHOULDER. Then begin your partial neck resizing proceedures. One step at a time.
IMO, you've got too much shit going on at once here.

When using Lyman type neck turners,FLRS using a standard die so you can turn all the way to the shoulder. Bushing dies dont size to the shoulder.

A wealth of information! Thank you all!

My SIL is shooting in 300 yard F Class with a factory Savage .223 w/ a 1:9 twist barrel. My reloads. After spending most of my life with up close double rifles, there are lots of things to learn.

Thank you again for your time and information.

You might want to search the archives at benchrest.com and at 6mmbr.com. Also there is an F-class forum now on benchrest.com.