New to Neck-Only Sizing ... How to Handle New Cases?

[Syncrowave]

Hey, all,

Recently got a rifle in 300WSM and, since it's the only gun I'll probably ever own with that chambering, I decided to get a Lee collet neck-sizing die (Lee #91019) to use for those loads. (It's a bolt gun.)

I bought a case of loaded Hornady ammo for it (since loaded ammo was quite a bit cheaper than any new cases I could find), so those cases will be fire-formed to my chamber when I reload them, but then I also found a decent price on some unfired (new) cases, so I bought those, too.

How should I handle the first loading with these new cases? Should I full-length size them, just to make sure I'm starting from a known state, or do you think I can get away with just neck sizing them? (I do also have a FL resizing die for 300WSM.)

This is the first time I've ever used a neck-only sizing die, so I've never run across this situation before.

Thanks in advance for any advice.

 

[jr600yd]

FL size everytime.

 

[ChrisNZ]

Agree. The FL die will do the complete job always, you won't be left wondering which die you should use/first/..

If you haven't seen it, search out the Cortina item on YT, something like "Stop neck sizing". He'll show you how to set up the FL die so everything will chamber properly without over-working the brass.

 

[Coyotefurharvester]

They should chamber fine(new brass) I would (dry lube inside necks first)use a mandrel to make sure the necks are round and inside neck diameter is 0.002 under bullet diameter. Prime,charge,seat,shoot.

 

[Big Mc]

Hey, all,

Recently got a rifle in 300WSM and, since it's the only gun I'll probably ever own with that chambering, I decided to get a Lee collet neck-sizing die (Lee #91019) to use for those loads.

I bought a case of loaded Hornady ammo for it (since loaded ammo was quite a bit cheaper than any new cases I could find), so those cases will be fire-formed to my chamber when I reload them, but then I also found a decent price on some unfired (new) cases, so I bought those, too.

How should I handle the first loading with these new cases? Should I full-length size them, just to make sure I'm starting from a known state, or do you think I can get away with just neck sizing them? (I do also have a FL resizing die for 300WSM.)

This is the first time I've ever used a neck-only sizing die, so I've never run across this situation before.

Thanks in advance*

Hey, all,

Recently got a rifle in 300WSM and, since it's the only gun I'll probably ever own with that chambering, I decided to get a Lee collet neck-sizing die (Lee #91019) to use for those loads.

I bought a case of loaded Hornady ammo for it (since loaded ammo was quite a bit cheaper than any new cases I could find), so those cases will be fire-formed to my chamber when I reload them, but then I also found a decent price on some unfired (new) cases, so I bought those, too.

How should I handle the first loading with these new cases? Should I full-length size them, just to make sure I'm starting from a known state, or do you think I can get away with just neck sizing them? (I do also have a FL resizing die for 300WSM.)

This is the first time I've ever used a neck-only sizing die, so I've never run across this situation before.

Thanks in advance for any advice.

FL ***** E V E R T T I M E Tommy Mc

 

[K22]

I Full Size all cases, all the time. However, I am very careful to only bump the shoulder when necessary. In my experience, full sizing produces the most reliable chambering reloads, an important consideration for hunters.

I use nothing but virgin brass from the same lot and dedicate a group of cases to a specific rifle. I rotate their use, so all cases receive the same number of firings and sizing's. I found this is the best way to maintain case consistency.

For virgin cases, I measure a sample of cases with a bump gauge and caliper to obtain the unfired case head space. I then set my F/L die to size the cases to zero bump. The reason I size virgin unfired cases is to uniform them to the same radial and head space dimension. I spot check them in the rifle (firing pin assembly removed) to assure optimum fit.

After the first firing, I measure a sample of fired cases (primer removed) to determine the fired case head space. I repeat the same process as above. Often, I can go several firings without having the bump shoulder. I believe this is because the F/L die is also sizing the radial dimension of the case which is often the culprit creating chambering difficulties. This also the reason I stop Neck Sizing about 25 years ago.

The process of making F/L die adjustments can be simplified greatly by using either Skip Shims or Redding Competition Shell Holders. This allows to one to make sizing changes without have to change the lock ring of the F/L die which can become tedious.

 

[209jones]

Neck only & dry lube is fine on a new case as it'll grow in length anyway, just to make sure you have a round neck and then set whatever tension level you want on the bullet, then chamfer and deburr them.
Also gives you a reason to check out the new cases for anything funky.
For myself, I also deburr flash holes, uniform primer pockets. I don't use new cases for big game hunting, always use once fired that are FLS'd.
Where I will use neck only cases, is with load development from new to 2nd shot usually, then FLS and set that die on third shot. I use a neck die for my varmint gun rounds, along with a neck bump bushing die, neck the first couple, neck bump the next 3-4 times, FLS them, start that cycle over again. They only have to shoot minute of gopher head to 2-300ish, not too fussy with them.
For the range guns, I usually neck first couple of shots, then FLS from there, unless I am using a pre existing load, then it's often only the first one.
As to Cortina's "don't neck size", he now has a rail gun he uses to fireform new brass in, uses a higher pressure than start load level pre-existing load in it, so, it's not like he's taking new brass out to a big match or to do development, he isn't.
Neck dies just save some work where it doesn't really need to be FLS'd, which saves a bunch of time and effort in lubing and cleaning, good for resetting neck tension on pulled bullet cases, fixing dinged case necks, fireforming. I pullled the decap rods out and use mandrels for expanding, as they are easier on the necks. I don't mind the extra step, it's fast and easy.

 

[ELR LVR]

Hey, all,

Recently got a rifle in 300WSM and, since it's the only gun I'll probably ever own with that chambering, I decided to get a Lee collet neck-sizing die (Lee #91019) to use for those loads.

I bought a case of loaded Hornady ammo for it (since loaded ammo was quite a bit cheaper than any new cases I could find), so those cases will be fire-formed to my chamber when I reload them, but then I also found a decent price on some unfired (new) cases, so I bought those, too.

How should I handle the first loading with these new cases? Should I full-length size them, just to make sure I'm starting from a known state, or do you think I can get away with just neck sizing them? (I do also have a FL resizing die for 300WSM.)

This is the first time I've ever used a neck-only sizing die, so I've never run across this situation before.

Thanks in advance for any advice.

FL size all new cases, always and forever,
You need to ensure the necks are round and that your headspace of the case is correct before fireforming
----------
You can neck size after fireforming, and even partially neck size if wanted
You will eventually need to bump the shoulder though after a few firings
In something like a 300WSM and how stout your load is
, this may need to be performed sooner than you think

 

[Charlie-NY]

I use Centry 21 mandrels and their moly neck lube on new cases. I see no reason to run new brass into a FL die because the brass is likely undersized already.

FWIW - in my earlier years, I would just load and shoot new brass with no prep. Yeah - a few case mouths would have minor dents but seating a bullet easily took care of that. Sometime we over think things.