Is the number of times fired all that important with cases?

[amlevin]

I read and hear all the time about how shooters keep their cases segregated by weight, volume, times fired, etc.

I've been wondering how important the "times fired" factor is if the others are equal. If cases are all of the same head-stamp, weight, volume, and have been annealed, does it truly matter how many times they have been fired?

I realize that firing work hardens the brass as well as a certain amount of thinning in the body but for accuracy, does it matter if there's no sign of case head separation (measured thickness)?

Just curious.

 

[watercam]

Good question. Work hardening can be helped with annealing of course. Frankly I keep my brass segregated within a couple of 100 count boxes and circulate the boxes in order over the course of the year of matches. Every case in each box has the same number of firings (more or less). When more than one case shows signs of age (loose primer pockets or cracks of any kind) the whole box is recycled. With Lapua .308 Palma brass I am getting about 13 firings with close-to-max loads.

 

[Laurie]

I'd say 'yes, it is important' for the precision minded shooter anyway. The longer the range shot over and the greater the need / scope for precision, the more important it becomes. (That is, forget about this if you're loading cheap milspec bullets to shoot in a well-worn .303 Lee-Enfield, 7.92 K98 Mauser etc.)

Apart from the overall case-life issue, it's very much about shoulder and neck area work hardening. That's partly determined by the number of firing / sizing cycles, also the amount of brass working in each cycle. A max-SAAMI factory chamber 308 Win resized using a standard factory die may see as much as 40 thou' total neck diameter change during firing / sizing / seating. Put that same case into a custom or minimum SAAMI chamber and resize with a bushing die reducing the neck O/D to a couple of thou' below that of the fired round might reduce the brass movement to just over a quarter of that encountered in the first scenario, so work hardening is much reduced. If the sizer die is set-up in the press using the 'default position', it may be pushing the shoulder back more than needed or is desirable. The more firings, the more change to the shoulder hardness and to the amount of case-body stretch and thinning that takes place as a result of a slack longitudinal case to shoulder fit.

Annealing should take a lot of the variables out of the equation, but I'd still much prefer to keep cases together, and anneal all cases in the ammo box in a single session.

The other reason for keeping them together is that neck-turned / fully prepped brass is also usually batched by case weight after all the preparation work is done.

 

[Down South]

The brass ive been shooting in matches lately has 9 firings on it, i actually mixed some in with brass that had just a couple firings and shot them together and didn't see any difference on target other than the pockets on the brass fired many times wasn't quite as tight as the newer brass......I anneal every firing......This is large primer Lapua brass, when the pockets start getting too loose i chunk em.

 

[Mega]

I believe it is important to keep a track of how many times your cases have been fired.

Precision Target Shooter, Hunter and / or Varmint Shooter it gives you a good indication of your case life and when, if you do research, how long before you expect failures. Many aspects you can pre-determine based on general use so say for example a typical case lasts 10 reloads you keep a close eye on those case as they approach a typical life. Of course many factors influence case life like those that insist on very hot loads can expect very short case life for one reason or another.

The last thing I want is an unexpected case failure.

 

[johara1]

I have loaded Dasher cases over a hundred times and never lost one for a split neck or loose primer, only if nicked from being dropped on the case mouth. If not too bad they will be sighters. Most destroy the cases with over working them, not annealing them and over loading……. jim O'Hara

 

[savagedasher]

I have loaded Dasher cases over a hundred times and never lost one for a split neck or loose primer, only if nicked from being dropped on the case mouth. If not too bad they will be sighters. Most destroy the cases with over working them, not annealing them and over loading……. jim O'Hara

+ 1 I don't know about the over loading. Larry

 

[Lapua40X]

I've been wondering how important the "times fired" factor is if the others are equal. If cases are all of the same head-stamp, weight, volume, and have been annealed, does it truly matter how many times they have been fired?

I'd say, except for the obvious points previously raised about keeping them separated so that they're life expectancy is essentially equal, "times fired" is not an issue when it comes to accuracy. When I have a hundred mixed cases for which I have no idea how many times they've been fired and one fails for some reason I have no way of knowing what to expect from the others in the box. I hate surprises at the range .....

 

[Laurie]

"times fired" is not an issue when it comes to accuracy. [Lapua40X]

That's not my experience, or that of most other long-range F-Class and FTR competitors. If the number of firings only affects remaining life, why are many of the world's top L-R competitors now annealing brass? Many top F-Open shooters anneal cases after every firing and say they can see the difference in reduced L-R elevations. Short-range groups, little effect seen if any, but L-R consistency? That's a quite different kettle of fish.

I used to have a manually operated straight-pull AR15 (our leaders don't trust us with gas operated versions in the UK) with a modified Wylde match chamber. After 5 firings / loadings, I would start to feel large variations on the amount of effort needed to seat bullets in Winchester .223 brass that had been sized with a standard Hornady sizer die. The variations felt through the press handle became greater on each subsequent reload, then at around eight to nine firings, the first neck split would appear on a fired case. If sound cases were kept going, and only the failed examples junked, some cases carried on for five or more firings after the first failure showing how inconsistent the work hardening process is. This applied to brass that had an identical load used throughout their lives, a very modest pressure 80gn Sierra MK / H. VarGet combination. At 100 yards, such well-past-their-best cases would often still produce astonishing groups, although the chronograph said the ES values were rising. 600 yards and beyond ..... that was a different story.

 

[Down South]

"times fired" is not an issue when it comes to accuracy. [Lapua40X]

That's not my experience, or that of most other long-range F-Class and FTR competitors. If the number of firings only affects remaining life, why are many of the world's top L-R competitors now annealing brass? Many top F-Open shooters anneal cases after every firing and say they can see the difference in reduced L-R elevations. Short-range groups, little effect seen if any, but L-R consistency? That's a quite different kettle of fish.

I used to have a manually operated straight-pull AR15 (our leaders don't trust us with gas operated versions in the UK) with a modified Wylde match chamber. After 5 firings / loadings, I would start to feel large variations on the amount of effort needed to seat bullets in Winchester .223 brass that had been sized with a standard Hornady sizer die. The variations felt through the press handle became greater on each subsequent reload, then at around eight to nine firings, the first neck split would appear on a fired case. If sound cases were kept going, and only the failed examples junked, some cases carried on for five or more firings after the first failure showing how inconsistent the work hardening process is. This applied to brass that had an identical load used throughout their lives, a very modest pressure 80gn Sierra MK / H. VarGet combination. At 100 yards, such well-past-their-best cases would often still produce astonishing groups, although the chronograph said the ES values were rising. 600 yards and beyond ..... that was a different story.

Hi Laurie,

I agree with what you are saying "if" the brass has not been annealed, but if the brass is annealed after every firing i think it doesn't make much difference. The brass i have 9 firings on (annealed every firing) has the same amount of force pressure on my 21st Century force arbor press as the brass with only a couple firings and my vertical in matches is the same with either brass.

 

[Laurie]

Assuming minimum neck-working and careful setting of shoulder-bump plus annealing, I'd broadly agree. I'd still rather keep my brass batched and together though. If something unexpected crops up performance-wise, it's a simple matter of junking that one box, not worrying about odd 'rogues' mixed up in several hundred expensive cases with a lot of work put into them.

 

[dragman]

For me it's a non issue.
Once I prep my brass for a gun and get it all fired and set I use it til I sell the rifle or the barrel's gone. I usually prep around 150 pieces and most of my guns never see more than 700 rounds give or take til I sell them. so I don't have that problem, If I get a new barrel I get new brass.

I however will not add brass to a gun that I am currently shooting if it wasn't all prepped I.E. turned together. If I have too I will then keep them separate.

 

[mikecr]

+1 johara1
Firing brass does not work harden it. It's your working of brass that does this.
Brass doesn't wear out & Fire-formed is fire-formed.
If you don't go too high in pressure, or over work your brass with continual changing/yielding, and if it's at all a modern design, with a chamber that's not stupid loose, cases can last forever -in fire-formed state.

I know there are many who assume ALL cases must be FL sized, and so ALL should be annealed, and constantly trimmed,, and replaced, etc.
I also know they don't know what they're talking about.

I fire-formed my 26wssm cases, and graphed all dimensions along side my reamer print to verify expected. That was a couple barrels ago, probably ~40 reloads by now on each, with zero change in dimensions, load, or results. I'm pushing 139LAPs at 3025fps, which is ~63Kpsi according to QL.
I do not FL size, nor do I anneal beyond initial prep for fireforming. Yet I knew by last barrel that these cases will last the rest of my life, and that there is no reason to prep any more cases.

The catch is you can't do this without a plan, which typically involves logical choices leading to outcomes.
When someone suggests they have to replace cases, it's because they chose that route.
That's all it is.

 

[Lapua40X]

If the number of firings only affects remaining life, why are many of the world's top L-R competitors now annealing brass?

Because annealing is the primary method applied to extending the life of brass. I would certainly agree that you should anneal your brass to extend its life. However, my point is that a hundred pieces of brass that have been well cared for, including annealing on a regularly scheduled basis, that have been fired ten times aren't any more accurate than a hundred pieces of brass that have been equally well cared for and fired twenty times.

 

[Laurie]

"Because annealing is the primary method applied to extending the life of brass."

I'd amend that to 'the accuracy life'. Worn out brass is worn out brass. I still believe that other factors can be at play. For example, my first 'TR' rifle was a simple .303 Enfield No.4 to 7.62 conversion done by Fultons of Bisley - chopped back furniture; heavy free-floating RSAF Enfield Lock hammer forged barrel; new extractor. Very common in the UK in the early days of TR.

WW brass would start to show incipient separation after 4 or 5 firings, one case only intially then a few each cycle, but it would only affect a percentage of cases, some lasting twice as long. This worried me as I thought my load was mild, and I was neck sizing so case-bodies would be fireformed. The problem was the weak Enfield action and rear-locking bolt with a lot of flex allowed ahead of the lugs - a mild 7.62/308W load was same or higher pressure than a service .303 Mk7 which the action was designed for. Because the lugs were assymetric, the bolt body flexed more to one side than the other allowing the case to bend marginally under peak chamber pressure - incipient separations marks formed an irregular line around the case, always higher on one side.

Once, I understood what was happening, I was less worried, if not exactly happy. But I was still puzzled as to why some cases lasted four or five firings, other 10 or more. Eventually, two reasons became apparent. One is that most smallarms cartridges produce a wide range of pressures in a batch irrespective. (If you ever find a copy of the rare paperback A-Square reloading manual which lists pressure ES and SD values for each load as well as the average, you'll see what I mean. Some spreads are scary!). The second reason was that there was random factor at work in how cartridges were chambered - a handful see a different position in relation to the lugs / bending action on every firing; a minority get most chamberings in or close to the same position more often so fail earlier.

Now, I'm not suggesting that your rifle has an action which behaves like an Enfield No.4's, but it will likely not provide 100% even support for the case-head. No matter how carefully you weigh charges, you will get pressure variations. Over enough firings, some cases will behave differently from the norm metallurgically as a result of these and other factors, so I'm not going to mix my brass up in a cardboard box, so that some by chance get 50 firings, and some five over a period of time.

Having weighed, measured, neck-turned and batched some thousands of cases over the years, they're not the same lot to lot either in their measurements, even with Lapua. If they come out slightly different weights and thickness, who's to say whether the brass alloy is consistent either over different lots?

To me, this isn't a big issue. I'd prefer to do it my way. If you want to mix your brass up and anneal every firing, 'GoodOnYer' as our Australian friends say!

 

[Mega]

"Too right Cobber" Bet the Yanks don't understand that....

 

[M-61]

QUOTE FROM LAURIE:
"The second reason was that there was random factor at work in how cartridges were chambered - a handful see a different position in relation to the lugs / bending action on every firing; a minority get most chamberings in or close to the same position more often so fail earlier."

Not sure I understand that correctly. I would have assumed those that get chambered close or to the same position would have a LOWER failure rate.
In a .222 Rem (easy on brass) I have a shell holder bolt face. I position every cartridge the same way 'Headstamp Up'. Or as close as my eyes can determine. I have no idea if this has added to the longevity or not.
I long ago lost track of the actual number of reloads on this brass. I started it solely to try and bring as much consistency into play as I could. Just my observations, with my method, with my brass, in my rifle.

 

[6BRinNZ]

I read and hear all the time about how shooters keep their cases segregated by weight, volume, times fired, etc.

I've been wondering how important the "times fired" factor is if the others are equal. If cases are all of the same head-stamp, weight, volume, and have been annealed, does it truly matter how many times they have been fired?

I realize that firing work hardens the brass as well as a certain amount of thinning in the body but for accuracy, does it matter if there's no sign of case head separation (measured thickness)?

Just curious.

At the end of the day I don't think anyone has run a head to head comparison. A lot of what we do is about ensuring factors are ruled out if a problem crops up. This is why i do it i.e. If I get an unexpected result I knows it's not due to mixed, unevenly fired brass..sometimes getting to the bottom of an issue is about ruling/having ruled factors out.

 

[bigedp51]

Case life depends on the construction of the cartridge case, chamber pressure, the size of the chamber and the size of the resizing dies.

I have gotten over 32 reloadings from a .303 British rifle by not using Winchester brass and using new Prvi Partizan brass that has thicker rims and much thicker case walls than Winchester brass.

Laurie, below is a once fired factory loaded Winchester .303 British case, it stretched .009 in the web on its first firing and the rifles headspace was set at just below .067. The best cases are Greek HXP cases that have a magic pixie dust applied to the brass mixture and are very long lasting but are hard to find anymore.

The Problem is our American commercial cases are not made to British military standards and this problem started 239 years ago when we had that little disagreement with King George.
(after this our American football players started wearing protective headgear and we changed how we spelled the word color)

As you can see below after 1775 we adopted the French Laissez-Faire metric system for our .303 British brass and chamber dimensions. :

The secret to long .303 British case life is using the right brass and drinking "cold" American beer. (and wearing protective headgear in Enfield forums)

Case life is like bending a paper clip being bent back and forth until it breaks, the secret to buying paper clips is to buy a good quality brand of paper clip and not bending the crap out of them. And compensating when firing civilian SAAMI cases in long fat military chambers and over stressing the brass.

The vast majority of the people who are in this forum do not have the above problem and have the reverse problem meaning skinny short chambers and fat, long resizing dies. (and argue about the semantics of shoulder bump)

Below standard .308 SAAMI chamber and reloading dies with the press reaching cam over and the dies adjusted as per the instructions.

 

[bigedp51]

"Too right Cobber" Bet the Yanks don't understand that....

We understand more than you think.

And my mothers maiden name is McVitty.

And the Titanic would never have sank if the ships hull had been made from Lapua steel. :