Thread: Full Length or Neck sizing. What is better and why?

Just wondering what your experience is with Full Length sizing or Neck sizing only?

Some pieces I have read suggest that FL sizing is harder on the cases and therefor reduces the number of potential reloads, but you get a more 'uniform' spread across the loaded rounds.

Others say that neck sizing is best as you getting a longer life out of the brass, and potentially better accuracy due to a tight fitting case in the chamber.

What are your thoughts and experience with this? Is it worth going out and buying a neck sizing die, even though I have FL dies already?

Thanks

If you FL size with a minimal shoulder bump, you get all the advantages of neck sizing without any of the potential downsides. Your cases will always chamber and extract smoothly and they'll last just as long (the primer pockets or necks will let go before the web does).

Originally Posted by Pommy

If you FL size with a minimal shoulder bump, you get all the advantages of neck sizing without any of the potential downsides. Your cases will always chamber and extract smoothly and they'll last just as long (the primer pockets or necks will let go before the web does).

What he said using redding comp shell holders

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Originally Posted by Pommy

If you FL size with a minimal shoulder bump, you get all the advantages of neck sizing without any of the potential downsides. Your cases will always chamber and extract smoothly and they'll last just as long (the primer pockets or necks will let go before the web does).

Good to know! But, what do you mean by 'shoulder bump'? Is it as simple as having a couple of mm gap between the shell holder and bottom of die so the shell doesn't go all the way in?

Thanks,

I will try find a link to using redding comp shell holders.
Once you use them there's no going back!

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This video shows you the easiest way to do minimal shoulder bump with the redding competition shell holders https://www.youtube.com/watch?v=ldtbsym650k
You could do it in a similar way where you just adjust the FL die in small increments until you effictievly achieve the same outcome.

You should always FL size, if done correctly it doesn't decrease brass life. Neck only can cause issues, rather than me explainin it just watch Erik Cortinas videos on the subject.
https://www.youtube.com/watch?v=lLG2kSrD40g
https://www.youtube.com/watch?v=htvk1UYOXm8

simple terms "shoulder bump" means pushing the shoulder of the fired case back a few thou using FL die, just enough so the sized brass chambers with ease. ie there is little or no resistance when you close the bolt.
You can test you're fired brass before re-sizing simply by chambering them. If the bolt close feels tight or requires some force then you need to bump the shoulder back. If there is no resistance on bolt close then you could simply neck size. If you get tight bolt close you should set you FL die up so that you only just moves the shoulder back slightly (like 2 -3 thou), then check the sized brass again by chambering it. If its still tight on bolt close then adjust your FL die down by 1/4 turn at most, and repeat until you get an easy close. Some of us like to target having slight resistance on close of bolt. Once you set up your die for that rifle it should be set to go for "minimal FL sizing and correct shoulder bump".

Create A “Custom Die” With A Simple Shellholder Change!

To maximize case life and the accuracy potential of your reloads, it's desirable to size fired cases the minimum amount that allows loaded cartridges to chamber freely.

Most hunters and many other shooters seeking smooth chambering reloads, full length size their cases each time. Since the interior dimensions of sizing dies are determined by the manufacturer, adjusting the shoulder setback is the only control a reloader has over how much a fired case is sized.
In the past, sizing die adjustment has been made through the trial and error method of rotating the die body in the reloading press. While acceptable results can be obtained using this method, precise adjustments are difficult at best.
Using this method, firm contact with the shellholder was not always possible. As a result, irregularities in brass hardness and thickness, as well as the uniformity and quantity of case lube affected shoulder setback. The resulting headspace variations created can adversely affect accuracy due to non-uniform primer/powder ignition. "Squaring" the die in the press is also precluded with this method of die adjustment.
[https://www]
To provide desirable shellholder-to-die contact during sizing, without excessively setting the case shoulder back, Redding now offers shellholders that are in increments of .002" thicker than the industry standard. The nominal thickness for industry standard shellholders is .125". (See dimension X on the shellholder diagram.) Our new Competition Shellholder Set includes five shellholders that are thicker than this in increments of .002". Therefore, the set includes shellholders that are marked +.002, +.004, +.006, +.008 and +.010, which is the amount the shellholder will decrease case to chamber headspace.
To select the proper shellholder for your particular firearm's chamber, start with the shellholder marked +.010. The shellholder should be adjusted to make firm contact with the bottom of the sizing die during the case sizing operation. Resize a case and try it (unprimed and empty) in the chamber of your firearm. If the empty case does not chamber or chambers with difficulty, switch to the shellholder marked +.008 and repeat the process. Stop at the shellholder that allows the firearm's action to close freely. Your cases are now being sized properly to fit your chamber with a minimum amount of headspace.



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I full length size for my lever action and single shot, and neck size for the bolt actions (then full length size after every 5 firings).
I use the Lee neck collet dies, which have the added bonus of not needing lube.
The bolt action rifles have never had an issue chambering a round (only owned them 30 years so still early days!), and consistently shoot three-quarter MOA so plenty good enough for hunting and the odd bit of paper culling

Chainsaw's advice is good but I'll add that you can often eventually end up in a situation where the 2-3 thou that normally works suddenly won't. That's because of base expansion, ie, the ~ 15mm above the rim has expanded and the FL die isn't exerting enough force to shift it back. In that scenario, you need to get a small base body die to fix the issue- use that first then your normal FL die.

My shopping list for target accuracy is (in order):
- a Wilson or Redding FL bushing die
- mandrel expander to optimise neck dimensions/tension
- small base body die ( or a custom version) for use only as required

Ideally you want to full length size your case just enough so it has the minimum necessary clearance in the chamber. This means every round is the same, as cases are always sized back to the same dimensions. Brass is worked as little as possible so lasts as long as it ever will.

However because all dies and chambers are made within a range of dimensions (SAMMI min-max) getting the perfect die fit can be hard. Sometimes with the correct shoulder bump your die might not even size the base of the case, leading to issues with chamber fit.

Personally I use a full length die and set it up so my bolt can just close with no resistance. (I think it's Alex Wheeler's YouTube video I watched.)

Greetings All,
Until recently I neck sized most of my cases, mostly using cartridge specific neck sizing dies. Recently I have moved over to minimal FL sizing using the Redding competition shell holders as I have found it hard to get consistent shoulder set back by just backing the FL die of the shell holder and it is a pain to constantly re adjust the die when there are multiple rifles for one cartridge. The only problem that has shown up is with the 6.5x55. It appears that the yanks use a shorter measurement head to shoulder for this cartridge than the scandinavian countries. My T3 has a tight chanmer but still needs the +010" shell holder to get close to the 0.002"shoulder bump, its about 0.003". This is with Redding dies, some older Lyman dies are worse. Both my M38 and a friends Ruger 77 have chambers longer by about another .004". For the old soldiers and their light loads I still neck size. For the .303 this is with a Lee Loader.
Regards GPM.

we all reinvent the wheel..my nosler manual #2 tells how to partial length resize....bump size..... long n short,when base touches instead of screwing in a turn you back out a turn....try it for fit in chamber and if it closes easy..lock it there and leave it alone.

Good advice here guys! The video links are really helpful too, thanks @Beetroot

Looks like a set of the Redding shell holders will be on the shopping list

None of them. I prefer a partial full recalibration, i.e. using the full recalibration dies I recalibrate 3/4 of the box. The reason is that if I do a full recalibration, I always return the casing to its near normal state and it doesn't take on the actual dimensions of my rifle's chamber. And if I recalibrate the neck, after a few reloads I'll have to do a full recalibration. The above is applicable to cases fired from the same rifle.