Annealed vs Not-Annealed. Some stats

[NamibHunter]

I don't quite follow what you're getting at.
In your 1st paragraph, you state that, "I do question the value of the AMP machine" &, you list the reasons why.
You then state that you think Litz results are flawed because he measures no improvement.
Admittedly, he used only 1 rifle & I believe 1 load but, his testing seemed perfectly valid as far as I can see.
It's a small sample however, he measured no improvement so, in his case, annealing or rather stress relieving had no marked benefits.
I'm not sure why you question his results.
Regards............Barelstroker

I have a high opinion of Bryan Litz. His research work and publications have moved the science and the sport forward.

In the interest of fairness: My concern with his AMP experiment is that he cleaned the barrel at the start of each test (clean the barrel, shoot a small nr of fouling rounds, then shoot annealed brass, clean again, shoot fouling rounds, shoot non-annealed brass). Some of my rifles take 20 rounds to copper foul and achieve their typical / normal speed, while others take 5. I am not convinced he fired enough fouling rounds to have representatives speed results. Minor complaint really, and he might well get the same result if he repeats the experiment with 20 fouling rounds and increase the round count by 3x. But worth redoing i think, just to be sure.

My opinion of the AMP machine is still the same: It is a useful productivity tool, but it is over priced. My partial results show that it will not generate an ES or group size reduction on par with say upgrading from a factory barrel to a Bartlein, or upgrading from random range pickup to premium brass and premium bullets.

I have used the AMP machine to anneal several hundred pieces of brass dozens of times, and i like the speed and convenience of the machine. I am also pretty sure it is a more consistent and accurate way to anneal brass. Shoulder bump is more consistent (but different compared to flame annealing, so adjust your dies). It is so quick that it is no burden at all to anneal every time. I intend to keep it. If it has improved my SDs, then it is too small a change to notice, as my logbook does not reflect it.

Subjectively, seating force appears to be more consistent than before (once i learned to clean out the necks post annealing), which must help at least a little bit.

I have recently improved my personal best and shot a series of sequential zero (<0.1”) and one (<0.2”) groups at 100 using Atips and 147 ELDMs, 7 groups in a row, all three shot groups, with two different rifles, on two different days. So maybe the AMP annealer is making a contribution to group size, but it is hard to be sure. Too early to tell.

 

[Redfoot Ranch]

I, for one, anneal every loading. I can 'feel' a difference , without any measuring, in the seating force necessary on a Co-ax. I do have a Wilson seater as well as a K&M arbor press with a small force pack setup, purchased for another purpose, that I intend to do some comparison testing on with annealed vs not annealed brass.

For my purposes, I do not feel spending another $1k+ on an AMP is justifiable over my homemade Elfster video-based annealer.

Your intended purposes and mileage may vary...

 

[elfster1234]

My EP 2.0 annealer should be going up for sale soon (next month or two) that will anneal from 50bmg to 300blk without having to add or remove any parts and adjusts from 300blk to 50bmg in about 30 seconds! Shipped 268.00 with brass pan and torch head!

I, for one, anneal every loading. I can 'feel' a difference , without any measuring, in the seating force necessary on a Co-ax. I do have a Wilson seater as well as a K&M arbor press with a small force pack setup, purchased for another purpose, that I intend to do some comparison testing on with annealed vs not annealed brass.

For my purposes, I do not feel spending another $1k+ on an AMP is justifiable over my homemade Elfster video-based annealer.

Your intended purposes and mileage may vary...

 

[Barelstroker]

I have a high opinion of Bryan Litz. His research work and publications have moved the science and the sport forward.

In the interest of fairness: My concern with his AMP experiment is that he cleaned the barrel at the start of each test (clean the barrel, shoot a small nr of fouling rounds, then shoot annealed brass, clean again, shoot fouling rounds, shoot non-annealed brass). Some of my rifles take 20 rounds to copper foul and achieve their typical / normal speed, while others take 5. I am not convinced he fired enough fouling rounds to have representatives speed results. Minor complaint really, and he might well get the same result if he repeats the experiment with 20 fouling rounds and increase the round count by 3x. But worth redoing i think, just to be sure.

My opinion of the AMP machine is still the same: It is a useful productivity tool, but it is over priced. My partial results show that it will not generate an ES or group size reduction on par with say upgrading from a factory barrel to a Bartlein, or upgrading from random range pickup to premium brass and premium bullets.

I have used the AMP machine to anneal several hundred pieces of brass dozens of times, and i like the speed and convenience of the machine. I am also pretty sure it is a more consistent and accurate way to anneal brass. Shoulder bump is more consistent (but different compared to flame annealing, so adjust your dies). It is so quick that it is no burden at all to anneal every time. I intend to keep it. If it has improved my SDs, then it is too small a change to notice, as my logbook does not reflect it.

Subjectively, seating force appears to be more consistent than before (once i learned to clean out the necks post annealing), which must help at least a little bit.

I have recently improved my personal best and shot a series of sequential zero (<0.1”) and one (<0.2”) groups at 100 using Atips and 147 ELDMs, 7 groups in a row, all three shot groups, with two different rifles, on two different days. So maybe the AMP annealer is making a contribution to group size, but it is hard to be sure. Too early to tell.

Yes well, I'd be lying if I said your observation wasn't valid. Cold, clean bore shots are well understood to influence group sizes & velocities. I can't be sure now but, I believe Litz was also looking at velocity ES/SD during testing.
As far as your personal findings, you're certainly not alone &, to be frank &, taking human nature into consideration, I strongly suspect there are a good many other AMP owners whom quietly doubt the validity of the AMP as well.
I do however, believe that the AMP does or could live up to the claims provided that the brass was of the same number of firings & preferably, annealed from once fired & between every firing. Other than those conditions which, the guys at AMP do clearly state as the method for "best results" all bets are off. I don't believe the AMP or, any other commonly used annealing method is able to bring brass hardness consistency to cases of different hardnesses.
Regards............Barelstroker

 

[Deleted member 10043]

Statistically, I'm I supposed to be seeing any material differences? Because I'm not.

 

[Barelstroker]

Statistically, I'm I supposed to be seeing any material differences? Because I'm not.

Well, I do have my own very unique take on this subject but, the last time I brought it up it caused a bit of a shit storm.
I don't own an AMP so I cannot state anything with authority other than to say that some of AMP's claims clearly contradict scientific study results on how brass anneals. They claim changes in the crystalline structure which, is certainly contradictory to the studies. At the temps & times they employ, it's safe to say that the brass would have to be very hard indeed to enter into recrystallization. Even then, the crystalline structure changes very little to the point where it is stated that observations must be undertaken with special x ray spectroscopy. During "stress relieving" no changes in the crystal structure are observed &, as far as I'm aware, it is still only theorized as to the mechanism involved.
Since most shooters who own an AMP anneal from brand new cases, it can be reasonably assumed that the brass is relatively soft which, directly affects the time to enter into the recrystallization phase which, is inversely proportional ie (harder=faster--softer=slower) in the exponential time domain &, can be assumed, in my opinion, to be "stress relief only" which, affects neither the crystal size, nor the malleability of brass.
I think it fair to say that, at very least, the AMP would never give obtuse results & I firmly believe that, it would certainly give reliable, dependable results, notwithstanding differing case hardness or number of firings between cases.
Regards.............Barelstroker

 

[Deleted member 10043]

All I'm saying is the OP isn't showing annealing has a unique advantage with reloading. Statistically, his confidence level is at least 90%. There are no material differences annealing vs not annealing with the resources he used. Keep in mind the brass he used was reloaded several times without annealing before the testing. He was careful during the reloading process. He even took it a step further and shot for groups that showed no material differences. That was the pudding on the cake. My take is reloading non annealed worn brass and then annealing for accuracy is not worth the effort.

 

[Barelstroker]

All I'm saying is the OP isn't showing annealing has a unique advantage with reloading. Statistically, his confidence level is at least 90%. There are no material differences annealing vs not annealing with the resources he used. Keep in mind the brass he used was close to retiring to begin with and had never been annealed.

I'm not at all disagreeing with you. As I stated earlier, I'm not at all convinced that "stress relieving" &, that's what it really is at those low temps & very short times, can make much if any difference to velocity ES or SD.
To give you an example of what something like an AMP does, I've 300 Lapua 308 brass in excellent condition, all sized & ready to load. They've been AMP annealed & seat a 168 grn Hornady Amax at about 180 Lbs. Neck ID is quite low at 0.302".
I took 2 more from the batch, confirmed the neck IDs again at 0.302", annealed those 2 cases the way I anneal. They both seat the 168gr Amax at 28-30 Lbs.
If anything's going to make a difference to velocity ES/SD, it will be 100% recrystallization simply because the normal way of "annealing" does virtually nothing as far as changing neck tension.
I believe people simply see what they want to see. It's a very common psychological reinforcement phenomenon. Happens all the time & is the reason placebos & control specs are used in experiments.
Every now again someone like LA260 shows up with some untainted data &, a rigid personality but, they're few & far between & sadly, mostly ignored.
Regards..........Barelstroker

 

[Deleted member 10043]

I was editing my post when you qouted me. I have a bad habit of doing that.

 

[Deleted member 10043]

Anyway, isn't the goal of annealing is to increase brass life and not necessarily accuracy? Personally, I choose not to anneal only because I don't want to. The test really doesn't tell us how many more accurate reloads he ended up getting with annealing that same brass.

 

[Deleted member 10043]

For all we know he got 5 more accurate firings with the 260 that was already at retirement when he started the test.

 

[Barelstroker]

Anyway, isn't the goal of annealing is to increase brass life and not necessarily accuracy? Personally, I choose not to anneal only because I don't want to. The test really doesn't tell us how many more accurate reloads he ended up getting with annealing that same brass.

Well, I've never thought annealing or rather, stress relieving, to be a waste of time &, there may well be other very considerable benefits, not least of which may be more consistent shoulder bump. It is my opinion that consistent shoulder bump may well play a greater role in velocity consistency. Maintaining consistent case volume is probably one of the main benefits. I know my cases size much more consistently since annealing the cases.
At very least, stress relieving definitely prevents neck splitting &, so long as primer pockets remain serviceable, cases life should be considerably extended.
When all's considered, I think it's definitely worth annealing.
Regards.................Barelstroker

 

[Barelstroker]

With regard to shoulder bump & case volume consistency, I've begun testing some sizing techniques including frequent cleaning of sizing lube out of the die & I'm waiting on the redding comp case holder set which, I think is a must in order to reduce &, hopefully remove the press & die friction inconsistency. I also have some new dies on the way which I will be trialling.
Regards..............Barelstroker

 

[Deleted member 10043]

I just use regular dies. I may shoot a little brake cleaner up a die once in a while. I keep my goal at sub moa down range. I'm no monument to excessive reloading techniques and I don't shoot hot loads to increase brass and barrel life. I try not to introduce anything new into the reloading process beyond the fundamentals. I stick with proven brass, powders, and bullets. It's been my experience everytime I have tried something new and exciting has turned into a real shit show. I can point to a lot of frustrating threads from others over the years to prove that point.

 

[Barelstroker]

I just use regular dies. I may shoot a little brake cleaner up a die once in a while. I keep my goal at sub moa down range. I'm no monument to excessive reloading techniques and I don't shoot hot loads to increase brass and barrel life. I try not to introduce anything new into the reloading process beyond the fundamentals. I stick with proven brass, powders, and bullets. It's been my experience everytime I have tried something new and exciting has turned into a real shit show. I can point to a lot of frustrating threads from others over the years to prove that point.

I hear you. At the moment though, I have to continue testing of my annealing method so, all this other testing can be paralleled.I'm doggedly sticking to keeping my case prep & loading as simple & streamlined as possible in the future when, I can settle on what works & find what doesn't.
Since much of our reloading & case prep techniques & tools are over 70 years old, I don't mind thinking out of the box & trying to expand my knowledge where I can. At the moment, I'm focussing on brass hardness consistency which, I believe I have accomplished using a very straight fwd, uncomplicated method.
Next is ensuring that the cases continue to perform normally as the load /anneal cycles continue. Neck tension is excellent & beyond my initial expectations.
During this ongoing testing, I will test some different methods of sizing to obtain improved case sizing repeatability.
This should be the last of the major testing with only minor adjustments expected.
Regards............Barelstroker

 

[Western Living]

I just finished reading this thread and the research on AMP's website. So why do the factories anneal their case necks? Both brass case suppliers and also loaded ammunition producers always anneal the necks. The factories that produce loaded ammunition are surely not concerned with brass longevity and preventing split necks on the 15th reload.

 

[Barelstroker]

I just finished reading this thread and the research on AMP's website. So why do the factories anneal their case necks? Both brass case suppliers and also loaded ammunition producers always anneal the necks. The factories that produce loaded ammunition are surely not concerned with brass longevity and preventing split necks on the 15th reload.

They anneal the necks because of a condition known since WWI as "season cracking".
It happens over a period of time with loaded ammunition. It can also be caused by chemicals such as ammonia & certain other chemicals which can be commonly stored in the vicinity.
As far as I've been able to determine, the prevention of season cracking was & is the only reason that the case necks are annealed by manufactures.
Regards.........Barelstroker

 

[Western Living]

If I understand season cracking accurately, it happens due to residual stress from forming the cases by cold drawing. Ammonia from horse urine attacked the copper in these stress areas resulting in cracks when the British stored their ammunition in stables during the Monsoon season in India. Once the cause was understood, it was more properly referred to as stress corrosion cracking. Storing the brass over horse urine certainly contributed to the problem developing, but I think case manufacturers came to recognize that the residual stresses were a liability with or without the urine. Annealing or stress-relieving solved the problem because it relieved the stress in the cases created when the necks were originally formed.

The more a case is formed by cold drawing processes such as forming shoulders and necks from straight walls or necking-down, the more residual stress is present. The amount of stress introduced by resizing necks depends on how far they are resized. Many SAAMI chambers are specified with +0.002" diameter tolerance, and bullets are often specified with -0.003" tolerance. So the actual chamber and bullet dimensions influence how much the brass is worked. Furthermore, brass thickness will influence how far the neck moves with each firing. How much farther it moves back during resizing depends on the die or bushing used. How far the shoulder is pushed similarly depends on the resizing process.

AMP's literature seems to be primarily concerned with work-hardening and HV rather than residual stress. Notably, they attempt to disprove the salt bath process as one which dependably anneals (softens) the neck: https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

It should be noted that work hardening and residual stress are not the same things. Residual stress does not likely have a very substantial influence on reloaders unless they are forming their own brass for wildcats. It may be possible to get a few more reloads out of some brass before neck cracking by heating for stress relief, but as some have noted, primer pockets often wear first. AMP, on the other hand, goes to great lengths to make claims about the benefit of very specific HV for various cartridges' brass. Their sales proposition depends not just on annealing, but on achieving the specific hardness their research is claimed to have determined to be optimal and that different specific amounts of energy are required for each cartridge type and even brand due to differences in mass. They determine the proper brass condition by hardness rather than a certain temperature.

When reporting range test results of annealed vs un-annealed: https://www.ampannealing.com/articles/57/annealing-under-the-microscope/ AMP's data is unconvincing to me. The accuracy results are influenced by too many other factors. The chronograph ES results aren't compelling -- ~1 fps difference in average ES.

While this topic is interesting, we can be certain that heating brass to relieve residual stress from cold forming certainly works to prevent stress corrosion cracking. There seems to be much less evidence that the effects on neck tension of consistently annealed brass will reduce ES when compared to consistently unannealed brass. Even less that annealing brass to a specific hardness will make me more accurate

 

[Barelstroker]

If I understand season cracking accurately, it happens due to residual stress from forming the cases by cold drawing. Ammonia from horse urine attacked the copper in these stress areas resulting in cracks when the British stored their ammunition in stables during the Monsoon season in India. Once the cause was understood, it was more properly referred to as stress corrosion cracking. Storing the brass over horse urine certainly contributed to the problem developing, but I think case manufacturers came to recognize that the residual stresses were a liability with or without the urine. Annealing or stress-relieving solved the problem because it relieved the stress in the cases created when the necks were originally formed.

The more a case is formed by cold drawing processes such as forming shoulders and necks from straight walls or necking-down, the more residual stress is present. The amount of stress introduced by resizing necks depends on how far they are resized. Many SAAMI chambers are specified with +0.002" diameter tolerance, and bullets are often specified with -0.003" tolerance. So the actual chamber and bullet dimensions influence how much the brass is worked. Furthermore, brass thickness will influence how far the neck moves with each firing. How much farther it moves back during resizing depends on the die or bushing used. How far the shoulder is pushed similarly depends on the resizing process.

AMP's literature seems to be primarily concerned with work-hardening and HV rather than residual stress. Notably, they attempt to disprove the salt bath process as one which dependably anneals (softens) the neck: https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

It should be noted that work hardening and residual stress are not the same things. Residual stress does not likely have a very substantial influence on reloaders unless they are forming their own brass for wildcats. It may be possible to get a few more reloads out of some brass before neck cracking by heating for stress relief, but as some have noted, primer pockets often wear first. AMP, on the other hand, goes to great lengths to make claims about the benefit of very specific HV for various cartridges' brass. Their sales proposition depends not just on annealing, but on achieving the specific hardness their research is claimed to have determined to be optimal and that different specific amounts of energy are required for each cartridge type and even brand due to differences in mass. They determine the proper brass condition by hardness rather than a certain temperature.

When reporting range test results of annealed vs un-annealed: https://www.ampannealing.com/articles/57/annealing-under-the-microscope/ AMP's data is unconvincing to me. The accuracy results are influenced by too many other factors. The chronograph ES results aren't compelling -- ~1 fps difference in average ES.

While this topic is interesting, we can be certain that heating brass to relieve residual stress from cold forming certainly works to prevent stress corrosion cracking. There seems to be much less evidence that the effects on neck tension of consistently annealed brass will reduce ES when compared to consistently unannealed brass. Even less that annealing brass to a specific hardness will make me more accurate

Yes, I admit, I am skeptical about some of their findings as well however, I'm cautious about concluding publicly that the AMP doesn't fulfill any of the claimed benefits. The problem as I see it is the temperatures they employ.
AMP have quoted 550c (1022f) as at least one of the temps they use &, although this is too low to guarantee 100% recrystallization within the times they publish, it may cause some amount of recrystallization, depending on initial brass hardness, however, herein lies the dilemma. Because the initial hardness is a significant factor, the results would tend to vary significantly between differing case firing lots. Then again, how much is "significant"? Although the HV results may be said to be significantly different, in practice, neck force seating results may not display the HV differences so vividly while still yielding positive results.
From all the information I've gathered, I'm confident in concluding that, temps of 650f to 750f & lower could not possibly yield any change in brass hardness within the commonly used times &, are questionable even to produce "stress relieving" however, AMP employs significantly higher temps which, most definitely take the brass into the exponential time domain, albeit for a short duration. So, for anyone to claim that the AMP makes no beneficial difference would be grossly irresponsible & unfounded.
I have never stated that AMP annealing has no benefit, simply because I have never proved that &, the temps they employ are indeed high enough to recrystallize in the right circumstances. Furthermore, I have never set out to rubish their claims either. I have merely stated some information based upon commissioned studies which I use to anneal rifle cases the way I have chosen to do so &, for my specific purposes.
With that said, I consider it reasonable & logical to be very cautious indeed about publishing negative statements concerning the AMP.
Sincere regards...........Barelstroker.

 

[Western Living]

We don't have to publish a negative statement. To make a sale to me, the onus would be on AMP to provide evidence their product and process provides a substantial benefit. I can claim that I have not seen any evidence from them of a benefit that would be substantial to me, without making a negative statement that generalizes about AMP as a whole. We might look and see whether competitive (winning) shooters are using it to their benefit, but I believe they have, as a group, proven to be unreliable in discrediting superfluous methods. A more reliable test would be that winners can't be without it. The competitors themselves can't afford to be the last ones to find out that they need it, but I can afford to wait until it's proven to be necessary.

 

[Barelstroker]

We don't have to publish a negative statement. To make a sale to me, the onus would be on AMP to provide evidence their product and process provides a substantial benefit. I can claim that I have not seen any evidence from them of a benefit that would be substantial to me, without making a negative statement that generalizes about AMP as a whole. We might look and see whether competitive (winning) shooters are using it to their benefit, but I believe they have, as a group, proven to be unreliable in discrediting superfluous methods. A more reliable test would be that winners can't be without it. The competitors themselves can't afford to be the last ones to find out that they need it, but I can afford to wait until it's proven to be necessary.

Yes well, I can't fault your logic there but, I think it reasonable to be cautious with public statements all the same.
On the subject of claimed results of brass hardness consistency with regard to Velocity & shot dispersion on target, I think that was originally claimed back in the 50's by 2 well known gentlemen in the shooting fraternity. It remains to this day to be a quite misunderstood phenomenon because of the counter intuitive association between "neck tension" & "brass hardness". Although hardness does indeed affect neck tension, it is mistakenly believed to do so as a direct result which, is not the case. Neck tension is mostly affected by brass hardness whereas, bullet seating force is mostly influenced by neck ID interference. It is the required neck ID which is governed to some degree by brass hardness. I say "to some degree" because the general hardness of the brass during commonly used annealing methods, doesn't change much, therefore, the ID interference does not need to deviate much from where the loader considers optimal seating force to be.
In continuance, it is brass hardness which drives brass tension which influences required neck ID which influences seating force.
So, if the brass hardness changes little then, the main influence must be the neck ID &, this is indeed the general consensus of handloaders.