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

[VarmLR]

Strictly speaking, there is no such thing as a truly consistent method if one gets pedantic about things.  The brass will migrate from head to mouth whichever method is used, so the case internal to external dimensions will alter very slightly shot to shot along the length of the case.   My own view, and I don't claim it's the right view, is that consistent neck tension and headspace is more important to my shooting than other considerations, along with consistency in internal volumes (again, within reason).  I used to neck size and tried collet neck sizers such as the lee one, which was fine with my .223 for a fair few reloads without the need to FLS but with my larger cals, I ended  up bumping the shoulders back every 3 to 4 reloads anyway, so reverted to FL sizing everything.  I few trips out after deer where the round refused to chamber ofter just a couple of hottish reloads in.308 convinced me to just stick with full length and I have noticed little, if any real difference in my SD/ES if being honest.  I start with decent brass, anneal every firing, FL size, check that headspace is no greater than 3 thou of the fire formed cases for the shoulder to chamber seating, and haven't worried about it beyond that.  Comp shooters may wish to do more.  The average Joe like myself probably doesn't need to worry beyond this.  There can be a tendency to over think these things and forget to concentrate on shooting technique, load consistency, including checking batch to batch powder variations and tweaking loads accordingly.

[Andrew]

I am liking this thread. I have been FL resizing for many years as a product of having multiple rifles in the same chambering. Accordingly I have switched from my youthful zeal to have each of my rifles with their own custom tweaked load, to reloading ammunition that would equal the best factory Match ammunition. It has made me pay attention to every detail and in turn, taught me what it important and what is not in reloading. It has certainly simplified my note taking. Instead of stacks of bound books (one for each rifle)I have a file card with the specifics of each load and a foot note as to how it performed in a given rifle. I have a 130 grain Creedmoor load that has been shot in four different rifles and all grouped sub moa and have rung steel to 900 yards. Does it give maximum accuracy in all of the four rifles? Probably not; but all grouped very well on paper so  I must be on the right track..~Andrew

[VarmLR]

I like your methodology Andrew and have resorted to much the same thing now.   More time practising and in the field for me has allowed real gains to be made in judging shots and shooting with more confidence.  If a load shoots moa at 600 yds, for most purposes that's fine with me.  If it doesn't it's more likely my loads are way out or I'm doing something wrong.  Either way, FL sizing and being consistent with brass prep/loading is usually good enough to get me into moa at these distances.  The rest is down to me.  Having fun ringing steel in less than perfect conditions over long distances is good practice and good fun...beats fretting over group sizes!

[Laurie]

As VarmLR says a couple of posts back, neck tension and 'headspace' consistency are the key items. I'd add working the brass as little as possible. Many people will tell you that 'headspace' is a technical term relating to the firearm chamber dimensions alone. Whilst certainly true for a gunsmith chambering a barrel or checking a firearm with gauges, in the wider sense and as I undertand VarmLR means - and I also do here - we're talking case fit in the chamber, specifically case shoulder position in relation to the matching section of the chamber. (Technically speaking, rimmed and belted designs headspace on the rim or belt at the rear end of the chamber, but sized case shoulder position is important here too for various reasons not least case life.

I used neck sizing alone for many years in standard SAAMI sporter and military rifle chambers. The main reason for this was using a Lee Hand Press, not a more powerful bench job, saw the Lee Collet die save a helluva lot of wear & tear on the upper arms, shoulders and chest muscles. It worked fine too. BUT ......! These were invariably mild loads that probably generated not much more than 50,000 psi pressures (for historic military arms, more likely 40,000 psi). As a result, there was very little shoulder movement.

Neck size cartridges for a modern rifle using loads that generate pressures equivalent to those in factory catridges (generally ~2,000 psi below SAAMI / CIP MAP celings and you'll soon find NS alone very unsatisfactory. Working up 260 Rem loads the other year, I did a box with the Collet die alone as I might have once done out of interest using once fired - in the same rilfe - cases. Around proved hard to chamber through generating resistance to final bolt closure because the case had become a mild crush fit in the chamber without any shoulder bump. Those that showed any resistance to chambering, invariably proved even harder to eject after firing, the bolt being very tight on upward movement and through obtaining primary extraction - no issue after that point as the tightness in the chamber wasn't through lower case body expansion (as in very high or over-pressure firing), but through turning the bolt against a case jammed into the front of the chamber length-wise. Other giveaways are witness marks on the shoulder and depending on the bolt-face design and protruding features, it scoring circular marks on the case-head. (These are sometimes wrongly diagnosed as an excess pressure sign.)

As well as being inherently undesirable, having half your rounds a crush fit, even if initially only slight, and the other half chambering easily without resistance breaks one of the key tenets of precsion loading - consistency. Why don't all cases exhibit the same fit or degree of tightness? Simply because smallarms cartridges generate considerable pressure ranges even when every care is taken in handloading, so shoulder movement varies from case to case on firing. (That's why SAAMI and CIP use Maximum Average Pressure limits.) I've also read that the case fit changes firing pressure produced - don't ask me how, but it's apparently so. The 'tighter' the round in the chamber, the greater the pressure generated on an average basis. Another cause of discrepancy.

The ideal situation is 0.001" clearance as based on measuring fired cases, and for every case to have that or something close, ie 0.001-2". This requires shoulder bump on resizing and moreover some canny equipment purchases and press use. Modern presses, brass, and good quality dies with the better case lubes will provide that degree of consistency. A generation or two back, handloaders who started measuring shoulder position after sizing found that getting better than a 5-thou' sized range was really difficult.

As well as providing the potential for better results proper shoulder control improves case life and reduces trimming frequency. This applies particularly to those types that don't headspace on the shoulder, rimmed or belted. Because the rifle manufacturer usually puts in much more shoulder area clearance than is acceptable in rimless set-ups, the 'standard' setting on a full-length die in the press, bottoming hard on the shellholder, can really push shoulders back far too much for the chamber's actual dimensions. The case fireforms back to the chamber size and is pushed back again on the next resize - do this a few times and you have an incipient case separation even with mild loads. I used a Hornady 'headspace gauge' (more accurately case gauge) on 7.62X54R cases I was loading for a Nagant M1891/30 sniper rifle I had until a few years ago and found I wasn't 'bumping' shoulders one or two thou',or even a few, but 20 thou' plus with the die on the default setting.

Add in the use of a bushing sizer, mandrel expansion, and annealing and brass will last a long time unless the pressures your loads generate expand the case-head and hence primer pockets. You can't do anything about the amount of neck expansion on firing seen in a sloppy factory or military chamber and hence the amount of sizing down needed, but you can often reduce overall brass movement here by getting on for half by abandoning a standard fixed neck diameter / expander ball type die for either a collet or bushing type. (it has become popular in some circles in North America with some cartridges to neck-size with the Lee Collet which really does do a good job especially if tweaked a little then to seperately body-size using a FL bushing sizer without any bushing fitted or a specialist body die that is a FL sizer but which doesn't touch the neck area.)

There is a half-way house, that I've tried, really like a lot, but which doesn't seem to have caught on much - the 'bushing-bump' type sizer die. These were available from custom diemakers such as Neil Jone only for a long time, but Forster now makes them for a limited range of cartridges and they're usually available off the shelf at Hannams Reloading. This is a bushing neck-sizer die but which also touches the shoulder area only of the case-body bumping it as in a standard FL sizer according to how it is set in the press. I ran a 308 Win F/TR rifle for some years using this die alone and getting multiple sizings / firings with easy chambering throughout despite using loads that QuickLOAD says are on or marginally above SAAMI peak pressure limits for the cartridge. (In the very strong small primer Lapua 'Palma' case.)

So ... going back to the beginning, if your loads are truly mild, the Lee Collet die used alone will usually give excellent results. Otherwise, neck-shoulder bump / FL size every time. If using any form of die that moves the shoulder, fired / resized case measurement and appropriate 'bump control' are very good ideas, essential for the precsion shooter. Likewise, only a fool will NS brass for dangerous game shooting, or for that matter not check that each and every loaded round chambers and extracts easily. The same applies albeit with less risk to life and limb maybe but to avoid injury to pride and wallet for those loading ammunition for expensive stalking holidays or important target competitions, especially those involving rapid fire such as CSR.

I'm not so sure about 338 LM as this large and high pressure cartridges has its own 'rules'. I suspect those with experience of it will advise FL sizing every time.

[VarmLR]

Hi Laurie

excellent post, and yes, what you surmised I meant was indeed what I meant.  It would be interesting to see how various other FL size dies compare.  I check my fire-formed using a Hornady comparitor, then set the press up so that I get about 1.5 to 2 thou', no more.  This on my Lee dies seems to equate somewhere around shell holder just touching the bottom of the die plus no more than 1/8th turn and not the 1/4 Lee suggest which bumps back a smidgen too far.   It will vary depending on manufacturing tolerances and this isn't surprising when you consider just how many dies are churned out from the same machinery which must be regularly checked to ensure it's within acceptable tolerances. 

[meles meles]

Many thanks for all these excellent contributions ! It seems as though we'll be full length sizing every time and "annealing" * very often...

 

* Stress relieving

[johnnyb0_1]

Full length size, then anneal.  Extends case life exponentially.  May as well be new brass, as long as you start with top quality brass, of course.  That gives you what everyone is seeking.... consistancy. Just my two hapeth worth. J.  

[furrybean]

Anneal and then size?

[Catch-22]

Yeah, definitely anneal and then size. Annealing replaces plasticity back to your brass necessary for proper sizing.

[furrybean]

7 minutes ago, Catch-22 said:

Yeah, definitely anneal and then size. Annealing replaces plasticity back to your brass necessary for proper sizing.

^^^^^ he’s right you know 

[meles meles]

We're not sure he is, wordwise at least. Some people seem unsure of the difference betwixt elasticity and plasticity, and stress relief and annealing.  By all means stress relieve and then size, but don't anneal. 

 

Pedantic ikkle critter aren't us? 😁

[Popsbengo]

For .308 (only one rifle in use) I've observed no benefit between bumping back the shoulder or just neck sizing with a collet die.  Never had a tight-close bolt.  I stress-relieve (😉) every 5 reloads and F/L size as the brass changes dimensionally during heat processing.  I'm still using my Lapua brass (large primer) after 10 reloads.  I load reasonably hot (43.5gn N140 under 155).

For .338 using Lapua brass I find I need to bump back 2 thou every time so I use a bushing die set-up. Unless I do that, I find the bolt just a tiny bit snug - ie zero headspace.  I also load quite hot so the brass (and my shoulder) gets a good work-out.  I'm "annealing" every time because .338 brass costs a kings ransom and I don't shoot it too often for it be a chore.

Badgers have to work while old dogs get to play all day and every day !