Jump to content
UKV - The Place for Precision Rifle Enthusiasts
meles meles

Neck size, or full length: has the jury decided?

Recommended Posts

Depending upon which forum or reloading manual one consults, either neck sizing only is the bee's knees, or full length sizing is the best thing for accuracy since sliced bread. Our thoughts are to neck size (.338 Lapua Magnum being the case in question) with an occasional full length size if cases start showing a reluctance to chamber. From what we have read, the arguments for neck sizing being more kind to the brass, and giving more consistent results because the case is formed to the chamber firing it, sound reasonable.

Share this post


Link to post
Share on other sites

Chicken ....... egg ......long ......string ......is 

personally I Full length size every time with all 7 calibre's I load for .who wants to be in the sticky bolt gang ! And knackered lugs .
it’s all about repeatability and taking everything back to Zero every time . 
 If neck sizing was consistent you would never Have to full lenth 

i thought neck sizing went out with dado rails .

the above is just an opinion. 

Share this post


Link to post
Share on other sites

Neck sizing - so last year ,,,

 

Full length every time 

Share this post


Link to post
Share on other sites

Theres a mid point, FL size but only enough to knock your shoulders back a few though which still allows for a good case alignment to your chamber.

If you use a FL bushing die you can adjust as above and still play with neck tension (if thats your pleasure) or even use a Lee collet die for sizing the necks.

 

Share this post


Link to post
Share on other sites

And that meles meles is judge and jury, only one way, full length 😃

 

 

 

Share this post


Link to post
Share on other sites

Until next year...

Do what works for you.  Neck sizing extends case life.  Knowing what you shoot Badger I wouldn't worry about the F Class latest fashion and what some shouty man on Youboob says.

I've done a comparison for myself with .308 -  No observable difference at 600yds.  Maybe with a tight chamber F class with a long barrel and everything else sorted to the last decimal, there's a value in the argument about returning brass to SAAMI/CIP every time but brass life is surely irrelevant to those at the cutting edge?

I resize .338 to knock back the shoulders 2thou from fire formed as it chambers better in my tight custom rifle. Does alright at long distance as you've observed.

Share this post


Link to post
Share on other sites
9 hours ago, Popsbengo said:

Until next year...

Do what works for you.  Neck sizing extends case life.  Knowing what you shoot Badger I wouldn't worry about the F Class latest fashion and what some shouty man on Youboob says.

I've done a comparison for myself with .308 -  No observable difference at 600yds.  Maybe with a tight chamber F class with a long barrel and everything else sorted to the last decimal, there's a value in the argument about returning brass to SAAMI/CIP every time but brass life is surely irrelevant to those at the cutting edge?

I resize .338 to knock back the shoulders 2thou from fire formed as it chambers better in my tight custom rifle. Does alright at long distance as you've observed.

Sage advice 🤔 😂

Share this post


Link to post
Share on other sites

What Pops said...........keep necking only until they just start to get a bit tight, then a gentle squeeze in a body die or the excellent Forster "Shoulder bump bushing die" until they just go in easily, and your brass will last and last..............

And don't forget to anneal the necks every 5 or 6 firings.

Pete

Share this post


Link to post
Share on other sites
1 hour ago, Re-Pete said:

What Pops said...........keep necking only until they just start to get a bit tight, then a gentle squeeze in a body die or the excellent Forster "Shoulder bump bushing die" until they just go in easily, and your brass will last and last..............

And don't forget to anneal the necks every 5 or 6 firings.

Pete

yep, I forgot to add "anneal",  works wonders for case life

Share this post


Link to post
Share on other sites
25 minutes ago, JabaliHunter said:

Can't see any good reason not to FL size unless you have a very poor match between chamber and die dimensions

I believe the presumption is that fire formed cases are somehow dimensionally unstable:  I've seen little good evidence to support that presumption.  Results from some F Class shooters is not evidence as we are not getting data from shooters that do not F/L size to compare (or I can't find sufficient to judge for myself).

When full length resizing we are impressing the dimensions of the die onto the case;  that therefore presumes the die is accurate and concentric.  This may be a big presumption with regard to some dies.  The quality of the brass's 'springiness' will partly determine the final dimensions.  I contend that F/L sized cases must have variation; how much depends on a number of factors.

Now if we suppose a die is machined to be exactly the same as a chamber:  that would satisfy the F/L presumption that we are creating exact ammunition with regard to every case.  I would argue that we're doing that in the chamber by fire forming.  F/L sizing cold brass vs  fire-forming brass under great heat:  which results in the most accurate and repeatable case dimension?  I'd like to see some real-world measurements.

When the powder ignites pressure pushes against the case with great force and heat.  For a F/L sized case in a slack chamber that distortion may not be consistent shot to shot.  If the case fits tight to the chamber, surely the pressure distortion is constrained to be more consistent ?

The heart of this issue to me is, that what ever we do in resizing, it's different to the actual chamber. 

Results matter, do what makes you happy and successful

Share this post


Link to post
Share on other sites

I'd like to add that IMHO, inconsistent neck tension will have more effect on MV, SD, ES or group size than miniscule variations in case volume or charge weight.

But then I could be wrong...................

Pete

Share this post


Link to post
Share on other sites
21 minutes ago, Re-Pete said:

I'd like to add that IMHO, inconsistent neck tension will have more effect on MV, SD, ES or group size than miniscule variations in case volume or charge weight.

But then I could be wrong...................

Pete

that makes good sense.  Neck tension affects starting pressure therefore burn quality.  I wonder though is this why jamming works well by effectively 'normalising' the starting pressure and reducing the influence of neck tension?  Some people seem to think light and lubricated necks are a good idea - I'm not convinced.

Share this post


Link to post
Share on other sites
5 minutes ago, Popsbengo said:

that makes good sense.  Neck tension affects starting pressure therefore burn quality.  I wonder though is this why jamming works well by effectively 'normalising' the starting pressure and reducing the influence of neck tension?  Some people seem to think light and lubricated necks are a good idea - I'm not convinced.

Your just a pair of “ neck sizing pikeys “ take your medieval ways and be gone .

Share this post


Link to post
Share on other sites
4 minutes ago, One on top of two said:

Your just a pair of “ neck sizing pikeys “ take your medieval ways and be gone .

😁😂

Share this post


Link to post
Share on other sites

Personnely i shoulder bump then neck size . If you had to be impatient you could have a custom die made from your fired brass - to have 1 operation not 2 . Or like they pointed out fl typeS bushing die . Thatl be 1 operation too .

Share this post


Link to post
Share on other sites

Light neck tension might have a similar effect to a jam.........the bullet would hit the lands very early in the burn cycle.

Pete

Share this post


Link to post
Share on other sites
8 minutes ago, Re-Pete said:

Light neck tension might have a similar effect to a jam.........the bullet would hit the lands very early in the burn cycle.

Pete

And it’s likely to not realise the full pressure potential either.

But...I have read that some US shooters (benchresters??) like to load long and use very little neck tension - essentially letting the lands seat the bullet. I’m unsure if this is an old/outdated technique or not...something I’ve read on the accurate shooter site I believe.

However, the above is not what I do or think is right.

Share this post


Link to post
Share on other sites

Me neither................just sayin'..............

Pete

Share this post


Link to post
Share on other sites
On 11/2/2019 at 1:03 PM, One on top of two said:

Chicken ....... egg ......long ......string ......is 

personally I Full length size every time with all 7 calibre's I load for .who wants to be in the sticky bolt gang ! And knackered lugs .
it’s all about repeatability and taking everything back to Zero every time . 
 If neck sizing was consistent you would never Have to full lenth 

i thought neck sizing went out with dado rails .

the above is just an opinion. 

There are just few circumstances in which I neck size, one of which is when I'm loading for some of my older 303 Enfields. In my Ross straightpull I use a "partial neck size" which was described by RCBS as screwing the die down to a US five-sent piece set on the shell holder. Otherwise, I FL resize everything.

I don't know if neck sizing is 'out' but a recent Lyman manual said that after years of comparison, they have found that neck sizing does not increases case life, nor does it increase accuracy. If you read the posts on reloading forums and start a tally, you might think that it causes most reloaders more problems than it solves. 

I recently shot some Hornady Precision Hunter and Hornady Match factory ammo in my 6.5 CTR.  I got ragged holes at 100 yards from the prone position. These loads were neither neck sized, nor loaded to X-thou of the lands. As JCS said: Consistency is the key.~Andrew

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use and Privacy Policy