What's a sensible frequency of annealing .308 cases?

[Bbear]

I'm not a competitive shooter, just a person that enjoys shooting as often as I can. Mostly 'short' range - 100-200 yards, but, some out to distances up to 1000. I don't anneal to improve accuracy necessarily, I anneal because I'm cheap and don't want to have to purchase more brass when the necks start to split. If it gets me better accuracy, great. If it has no effect on accuracy, I'm fine with that as well.
I will anneal my 308 cases after 2 firings.

 

[Campbell]

Friends

Many thanks for your very informed input!

The reason for my thread is that I am experiencing different bullet seating forces despite me preparing (excluding an annealing process) cases in a consistent manner

Cam

 

[retired]

what is your accuracy requirement ?
since the brass hardens a little on each firing, the neck tension
changes after each firing.
only you , your load, your target and your rifle can answer the question.
for the most consistency,
after every firing.

Please will you advise re the above-mentioned title.

The load is 47.6 grains of RS52 behind a 155 grain bullet and the cases are Lapua Palma

 

[Mozella]

............ snip.........................
And there are metallurgical reasons NOT to anneal every firing.

I'm not a metallurgist; however, I did take a few classes in metallurgy as part of my formal education. One of the things we studied was the annealing of cartridge brass. Admittedly that was a long time ago, but metallurgy doesn't change in the same way as modern electronics so I assume that much of what I learned back then is still valid.

I've never heard of "........... metallurgical reasons NOT to anneal every firing."

What, exactly, are these reasons you mention?

 

[riflewoman]

The metallurgical reason is if the brass is annealed every firing the critical temperature is above recommended annealing temperatures. To get critical temperatures down and to get enough stored energy in the grain structure there needs to be about 40% cold work remaining in the grains. With only about 12-15% per firing cycle there isn’t enough energy to get recrystallization below 1000-1100 F. Without recrystalization, you can’t remove the dislocations. It is what a metallurgist calls a “sub-critical anneal” or “stress relief”. The stresses are gone but the increased strength (bullet pull) will remain because much of the hardness remains. When the metal recrystallizes the metal relaxes to its basic strength levels. The problem with not removing the dislocations is that the metal cracks early due to accumulated dislocations. Probably won’t affect case life much but the increased stiffness will remain.

 

[dickn52]

Don't do .308. But my .223's get annealed every time I shoot them.

 

[carlsbad]

every firing.

 

[DirtySteve]

Accuracy a side. I anneal every time. I want to prolong the case life. Them cases aint cheap. But is you get enough reloadings out of them, that makes them cheap.

 

[retired]

that is a very big "if"
and has nothing to do without many times but how poorly done.
one more vote for the amp!

The metallurgical reason is if the brass is annealed every firing the critical temperature is above recommended annealing temperatures. To get critical temperatures down and to get enough stored energy in the grain structure there needs to be about 40% cold work remaining in the grains. With only about 12-15% per firing cycle there isn’t enough energy to get recrystallization below 1000-1100 F. Without recrystalization, you can’t remove the dislocations. It is what a metallurgist calls a “sub-critical anneal” or “stress relief”. The stresses are gone but the increased strength (bullet pull) will remain because much of the hardness remains. When the metal recrystallizes the metal relaxes to its basic strength levels. The problem with not removing the dislocations is that the metal cracks early due to accumulated dislocations. Probably won’t affect case life much but the increased stiffness will remain.

 

[Bart B.]

My remarks:

The metallic sighted rifle put all shots in about 5/8ths inch at 100 yards.

Another like test with 56 rounds from a machine rested rifle went in 3/8ths inch at 100 yards with Sierra 168 HPMK bullets.

And there were no results using annealed brass for comparison. Why?

That info was put up to show over 90%+ of center fire reloaders that annealed cases are not needed to produce accuracy most of them probably won't better hand holding their shouldered rifles. They're not shooting smaller cartridges free recoil that virtually eliminate human variables enabling groups averaging in the 1's and 2's at close ranges.

Those agg'ing in the 2's have some in the 1's and some in the 3's. That 3/8ths inch 56-shot group had eleven 5-shot groups plus 1 extra shot. Some of those 5-shot groups were in the 1's and 2's. Sierra's rail guns shot 168 HPMK bullets that well to pass quality tests with 10-shot groups in their California plant's 100 yard range.

 

[HomeSlice]

No, that is definitely not consistent.

<snip>

Having said all that, I'm reminded of the test Bryan Litz performed. He shot quite a few rounds in several different calibers and tried to measure the accuracy degradation associated with not annealing every time. I think he tested annealing every time, annealing every five times, and every ten times if I remember correctly. Something like that anyway. Bottom line: If there is a difference, Mr. Litz was unable to detect it. Personally, I believe that annealing is like a lot of stuff most of us do, like deburring flash holes, uniforming primer pockets, and so-on. The effect is almost surely positive but actually measuring the improvement of any one step is impossible when our testing procedure involves a human shooting at a far distant target through an uncontrolled atmosphere. It should be noted that Mr. Litz didn't claim that annealing each time doesn't work. He was simply unable to detect the improvement, if any.

I wonder, after performing this experiment, if Mr Litz still a Neal’s his brass?

 

[Mozella]

I wonder, after performing this experiment, if Mr Litz still a Neal’s his brass?

I don't know, but I continue to anneal mine. Here's why.

We all know that major factors, such as charge weight variations, are things that we can measure. More often than not, we see definite changes in MV as well as changes in group size when we test different charge weights. But anyone who has done load development in a serious way knows that there are pitfalls. If you use a coin to judge your performance, this may not apply to you. But if you scan and measure your test targets with a computer program and then study the results in a spread sheet, you will frequently encounter data that just doesn't fit as nicely as you might hope.

One big reason for those sometimes mysterious and frustrating test results is the fact that we normally test by firing our hand loaded ammo out of a rifle held by a human and launch bullets at a target some distance away as it travels through an unmeasured and unknown atmosphere. Plus, when we're testing charge weights, we use brass with variations in case volume (even if we sort them), bullets with weight, size, and shape variations (even if we sort them), and we shoot these test rounds through barrels of various temperatures and various degrees of fouling, just to name a few variables which are not fully controlled.

Sometimes these variables add up to overwhelm our expected test results and produce the dreaded "flyer". It goes without saying that none of us on this forum would ever flinch and produce a shooter-induced wild shot........... we're way too good for that, aren't we?

In other words, as we test one thing, we are unable to control a whole bunch of other stuff and that introduces noise, to one degree or another, into our test data.

So when we test charge weight variations, we are normally able to come up with good answers and make reasonable decisions 'cause charge weight is rather straightforward. But what about more subtle factors? For example, what happens if you change your neck cleaning procedure? Let's say you've been cleaning cases with the wet SS method and counting on your Moly coated bullets to serve as seating lube. Now you want to try dry tumbling and swabbing the necks with some sort of magic lube in order to seat non-coated bullets. It's impossible to guess if you would expect to see and measure an improvement or a decrease in group size, MV, or anything else. All most of us could say is that the change, if any, is bound to be small; much smaller than a .1gr change in charge weight for instance.

In addition, do you think you can measure changes in your case neck lube process? Well, maybe you could, but I wouldn't bet on finding a genuine answer before you wear out your barrel. There MUST be a difference, right? The same can be said for flash hole deburring, primer pocket uniforming, and a whole lot of other things we do in the search for that winning edge. That includes annealing frequency.

Trying to isolate a single factor which we expect to have a tiny effect on performance is a fools errand. There is just too much "noise" in our normal testing procedures. So most of us use common sense along with a bit of superstition. I believe that careful brass prep helps so I uniform my primer pockets. I also believe that annealing every time helps, so I do that every time. Can I prove that these two steps help or any of the other countless steps I take in the course of a reloading cycle? No, I can't.

But I can say for sure that my current reloading procedure produces WAY better results than when I first started reloading back when I was using the cheapest bullets and measuring powder with a Hornady Lock-N-Load case activated powder dispenser on a progressive press.

It should be noted that Mr. Litz didn't prove that annealing didn't do any good. All he found is that he couldn't measure the difference, if any. I suspect he would get the same result when testing primer pocket uniforming too. The expected improvement is just too small to tease the data out of the rather significant base noise. But that doesn't mean that tiny, difficult-to-measure improvements don't add up.

 

[JimSC]

Well Brian Litz has data to prove all this hubbub about annealing doesn’t affect accuracy.

“The Modern Advancements series of books can best be described as a journal of his research and development activities. They explore common questions such as the effect of barrel twist at longer ranges, how muzzle velocity affects hit percentages, laser range finders, etc. Volume II explores handloading techniques and what the shooter can do to produce higher quality ammunition. The key objective is to approach the subject matter in a “Myth Busters” science driven approach. They take commonly held beliefs, explore the science behind them and share the results of their testing. One of their more scintillating findings involves annealing and their discovery that it does not have a noticeable impact on accuracy. We can just see the forums lighting up on that topic!”

In Modern Advancements In Long Range Shooting Vol II Mr Litz has limited data on annealing. His only full test was on .223 Remington. He also tested .308 but did not publish the data for it because he used the wrong settings on the AMP. You are correct in that he found no difference in velocity SD and brass wear on 10 times fired cases in a batch that was never annealed, a batch that was annealed every firing, and a third batch that he annealed after the fifth firing. However his testing was limited due to time constraints and plans on doing more extensive testing for a future book. I may stop annealing if Mr Litz comes out with more data in a future book and says it is worthless but until then I plan on annealing after every firing. It takes me less than 15 minutes to anneal 50 cases on my Anealeeze and propane is cheap

In regards to the OP I have some old Lapua .308 Palma brass that has over 20 firings and still good. It was annealed every fifth firing using the torch and socket on a drill method and is still excellent brass

 

[riflewoman]

I don't know, but I continue to anneal mine. Here's why.

(Snip)



I also believe that annealing every time helps, so I do that every time. Can I prove that these two steps help or any of the other countless steps I take in the course of a reloading cycle? No, I can't.

The problem with shooters in particular is they hold to myths and beliefs like it’s some sort of religion. There IS science to annealing brass. And most of these theories can be confirmed or disproven by analyzing data or conducting experiments (not involving shooting) to determine if one method or another is better or worse or if it really makes any difference. But shooters don’t, won’t, or can’t do the data analysis and have no idea on how to determine the changes to the metallurgy they create. So they rationalize a belief based on what they want to believe. This isn’t limited to annealing either.

So believe what you want. It doesn’t make it absolute truth.

 

[LHSmith]

The metallurgical reason is if the brass is annealed every firing the critical temperature is above recommended annealing temperatures. To get critical temperatures down and to get enough stored energy in the grain structure there needs to be about 40% cold work remaining in the grains. With only about 12-15% per firing cycle there isn’t enough energy to get recrystallization below 1000-1100 F. Without recrystalization, you can’t remove the dislocations. It is what a metallurgist calls a “sub-critical anneal” or “stress relief”. The stresses are gone but the increased strength (bullet pull) will remain because much of the hardness remains. When the metal recrystallizes the metal relaxes to its basic strength levels. The problem with not removing the dislocations is that the metal cracks early due to accumulated dislocations. Probably won’t affect case life much but the increased stiffness will remain.

If I understand you correctly, those who anneal too often will experience cracking in the neck area more frequently than those who anneal periodically. I have not seen this.
Even if I found this to be the case, I would still anneal after every firing if my targets prove the results from more uniform neck tension.
I am convinced most engineers do not truly understand what we as BR competitors are trying to do. Why else would virtually every scope manufacturer put out a product that is not capable of holding POA to the degree it takes to be competitive, or why would powder manufactures fail to replicate the burn rate of an obsolete proven powder? Why do cartridge manufacturers insist that nothing has changed in the brass composition or annealing procedure over time? Yet hundreds of results-oriented competitors who believe in minimizing every possible variable in the reloading/ shooting process come to conclusions (based on real world experience) counter to what the manufacturers claim.
It is NOT internet folly. Only a very small minority of BR competitors view sites like this, many even despise it because so much of it is disinformation. Yet those same competitors individually come to the same conclusions on the range where it matters.

 

[JimPag]

And the results using annealed brass for comparison?
In score BR the 30 BR dominates. Most anneal their brass periodically if not every firing. To be at all competitive in registered matches one has to have a rifle that agg's below 0.200" for 25 shots for record. Most load in the upper end (high chamber pressure) because that is predominately where the best accuracy lies. Ease of chambering and extraction is extremely important in order to get rounds fired in a chosen condition (no bag upset). Properly annealing cases is a necessity.
I would imagine fighting with the bolt is a huge deterrent to shooting well in any discipline. Annealing provides insurance that sticky cases are unlikely to happen.

Well Lamar. I asked Dean how many times he anneals his brass in a season of shooting and he said he does it only twice. You can't argue his success rate. But what works for him might not work for a lot of other people. There are too many variables in this game to say when to anneal and at what intervals. Nobody can say for sure and if the do they are full of shit. I read the experts telling you that you have to trim all your cases to the same length. I did an experiment one day where I took 18 30BR cases, all fired 6X and I trimmed 9 of them to exactly the same length, 1.520 and the others where all over the place from 1.520 to 1.529. Fired three 3 shot groups 3 times with the ones that were trimmed and the ones that were all over the place length wise. There wasn't one bit of difference in the groups, not one. There was no clear advantage between the 2. When I started playing this game 5 seasons ago, everyone was willing to help and everyone has the same basic knowledge to get a rifle up and running and competing but lets face it some people have more than others. When I want answers to something, I'll ask different shooters a question and I'll listen to their answers, BUT in the end, I'll ask the shooter or shooters who consistently wins what to do and give it a try by what they say. Most of the time I have found that if I apply to what they say it has worked and their answers were a little different than what most of the other shooters answers were.

 

[LHSmith]

Well Lamar. I asked Dean how many times he anneals his brass in a season of shooting and he said he does it only twice.

That answer does not tell you much. We don't know for fact how much brass he preps per season, how many different barrel/brass combinations he uses in a season, and most successful competitors will not give full disclosure on what works for them nor should they be expected to. I base my regimen only on what works best in practice and matches.
I believe your test on case lengths has too many variables. Tunnel testing by Lokker and Neary showed otherwise. Trimming is so easy to do, so I elect to eliminate this one variable.

 

[JimPag]

That answer does not tell you much. We don't know for fact how much brass he preps per season, how many different barrel/brass combinations he uses in a season, and most successful competitors will not give full disclosure on what works for them nor should they be expected to. I base my regimen only on what works best in practice and matches.
I believe your test on case lengths has too many variables. Tunnel testing by Lokker and Neary showed otherwise. Trimming is so easy to do, so I elect to eliminate this one variable.

Well I'll disagree. To me if it's working at the end of a match I'll know it. I've proved to myself that doing a lot of these little things is a lot of bunk. Tunnel testing is one thing, shooting a match in the real world when there's a lot going on is another. As far fellow shooters not telling you everything, that's another story. They are not using my barrel and I'm not using theirs. I laugh at some of these guy's when they think that their loads are top secret and they won't tell you what they are using. Let's face it because as you know each barrel is like a human. Each is an individual and each have different tastes or loads in a barrel's case which it likes or it doesn't. I know who I can and can't trust to give me a straight answer by now when I need some advise. The bottom line is anyone can give advice on what to do or what not to do in this game but in the end if your not a consistent shooter, then all your philosophies ain't worth a plug nickel if you can't apply them to your game and make them work for you.

 

[LHSmith]

Well I'll disagree. To me if it's working at the end of a match I'll know it. I've proved to myself that doing a lot of these little things is a lot of bunk. Tunnel testing is one thing, shooting a match in the real world when there's a lot going on is another. As far fellow shooters not telling you everything, that's another story. They are not using my barrel and I'm not using theirs. I laugh at some of these guy's when they think that their loads are top secret and they won't tell you what they are using. Let's face it because as you know each barrel is like a human. Each is an individual and each have different tastes or loads in a barrel's case which it likes or it doesn't. I know who I can and can't trust to give me a straight answer by now when I need some advise. The bottom line is anyone can give advice on what to do or what not to do in this game but in the end if your not a consistent shooter, then all your philosophies ain't worth a plug nickel if you can't apply them to your game and make them work for you.

Glad you have the game all figured out.

 

[dcali]

I believe the answer is either every time or not at all. It occured to me that nobody is really trying to quantify the effect of annealing on seating a bullet, so I did a stress analysis on a case neck:

http://bisonballistics.com/articles/case-neck-tension-a-stress-analysis

What I found jibes well with my experience and some anecdotes over the years. A couple thoughts:

One is that if you anneal at all you will yield the case neck when you seat a bullet. So if you choose to anneal, you had better be consistent about it. Because inconsistency in hardness will lead to inconsistency in neck grip if you yield the neck.

Another is that if you don’t anneal, it becomes possible (possibly after a few firings) to seat a bullet with light tension and not yield the case neck. This is going to be more consistent than any other method in my opinion (this is just informed speculation) and it turns out that light neck tension and many times fired brass was (or still is? I don’t keep up) a typical recipe in short range benchrest. The trick is that it has to be light tension - around .001 depending on caliber.

Personally, I think annealing is sort of like moly was back in the 1990’s and I wouldn’t be surprised to see it fall out of favor in the future just as moly did.