An Essay on Annealing for Accuracy

[Guest richness]

An Essay on Annealing Brass for Improved Accuracy. Research by Simon Mearns (si-snipe) Written by Richard Utting (richness)

 

There is a lot of rubbish and hearsay when it comes to the subject of annealing brass for improved accuracy.

 

We did our own testing and came up with some results we stand by and serve us well now. When I say we, I mean predominantly Simon Mearns (si-snipe on the forums) I had my own views and experiences on the subject but Si did more work and testing and came up with better results. I tried his techniques and have now incorporated them fully.

 

We found that the “feel” of the seating die became much less consistent as the number of times the brass had been reloaded increased. People were worrying about how long they could get their brass to last; we were only concerned with that inconsistent feel leading to/caused by inconsistent neck tension as the brass “work hardened” ie became brittle as it was flexed in and out by resizing/firing/resizing. As sure as god made little apples, variances in neck tension reduce accuracy.

 

I had previously tried annealing, knackered my brass and then simply bought more rather than messing on with it more. This, of course, is what most people end up doing! The problem for us is that we were getting slight variations in neck tension after only one or two firings. We are looking for the Nth degree of reloading consistency with any little factor, however minute, being given full attention. Yet we didn’t want to buy new brass every other shot….

I tried using a candle and heating the neck until the base was too hot to handle, then dropping into water to quench. This worked a bit but was incredibly slow and there was wax everywhere. I felt confident that I wasn’t overheating and ruining the necks, but I wasn’t sure that they were all being done properly.

 

Meanwhile, Si-snipe was doing his own research.

 

He found that the way to do it was using a small blow torch.

 

You need natural light and clean brass.

We rotate the brass under the flame. I use an electric screwdriver with a socket in the end (size to fit the brass) and spin it under the flame.

What you’re wanting to do is heat the neck to the point where the brass reaches the temperature where the metallurgic realignment happens. This is fixed. Miss it by 10degrees and it simply won’t occur. You MUST get hot enough. Not very much hotter, though, and the brass breaks down and is far far too soft and is utterly ruined. And dangerous.

 

THE KEY TO THIS IS THE COLOUR CHANGE and it is dead simple:

 

Watching the brass as it turns in the flame, the neck will turn a rich BLUE and roll down the neck and shoulder. When it does this, quench it.

 

3or4 seconds more and the neck will go cherry RED. This is RUINED. BIN IT

 

The main pitfalls are:

 

The necks being too dirty to see the colour change

 

The light being insufficient and the subtle blue colour change not being spotted properly. I find the light from a window to be perfect.

 

NOT going for long enough. In 243 and 6.5x47, you need to be heating the brass for nearly 10seconds sometimes…it feels a long time. If you don’t see that subtle blue ring roll down the neck, you haven’t annealed. In 204ruger, it happens in just 3or4 seconds and is ruined in 10. It is essential that you observe the colour change.

 

After quenching, you’ll find a lovely multi-coloured ring on the shoulder (just like brand new Lapua brass has)

 

Now, with the freshly annealed brass, I find greatly reduced the number of rounds that have incorrect seating depth due to different neck tensions. The seating die feels dead consistent and over the chrony the FPS spread is knocked right down.

 

You can anneal as many times as you like. We have found ZERO difference in the strength of the brass/primer pocket etc…it just has no downsides. We now do it every single reloading, simply because the figures prove to us that the rounds are more uniform.

 

I hope this helps some of you give annealing a crack. The advantages to the long range rifleman are manifold. The disadvantages are nil apart from the extra time it takes.

[6.5shooter]

Thanks guys!

Something I just have no experience from doing and would like to start it for my 6.5x47 brass but did not want to buy an expensive machine for.

Regards

 

Garry

[Si-Snipe]

Yeah I fully agree with what Rich was written above. It is good that we are both researching through the effects of annealing together as we are able to backup our findings more so with more results and information.

I think many people are worried about damaging brass or annealing inconsistently i.e. annealing some and not getting others up to temperature which would give negative results to the batch.

The light for annealing must be good. I know some even anneal in darkness and wait for it to glow but in my mind this is getting to close to the point of 'too much heat'.

I now use a drill and use the clamp of the drill head its self (not a socket) to lightly grip the case, I use only hand tension and spin the drill to grip it. This allows the case to rotate very concentrically (compared to the socket method) and allows you to observe the colour change more closely without cases wobbling slightly in the socket.

I also find that keeping the speed slow is better for observation but quick enough to keep it even. 1-2 rotations per second is what I prefer.

Hold the case/drill either at an angle of horizontal - whichever gives you the best light for observation.

Its not so critical that if you go beyond the dark blue colour change for a second that the case is ruined, otherwise myself, Rich and others who anneal would probably be throwing away cases everytime. In fact I have only thrown one away and that was when I experimented to see what happened if I deliberately left it in the flame for another 5 secs.

I also only centralise the flame on the centre of the neck as the idea is not to hit the shoulders (unless you are forming another case through a series of dies and want the shoulders really supple for maximum manipulation). Only the neck needs annealing for the performance enhancement as this controls the consistency of bullet release.

Rich also pointed out something I have recently been thinking about and this is if you mix a couple of batches of brass this would lead to obvious differences in neck tension but annealing will re-set these variations back to a controlled tension. So it can also be used to repair mis-batches of brass or brass received from a fellow shooter.

I am hoping to be able to maintain the same accuracy in my Lapua cases until the brass fails rather than suffer a gradual degrading of accuracy due to inconsistent neck tension leading to increased variation in velocity/vertical spread.

Cheers,

Si

[Si-Snipe]

I will also add that I can anneal 50 cases in 25 minutes - so the way I see it time is not an issue. I then tip out the water and leave them in a sieve in the airing cupboard for a day.

[Guest richness]

See, I told you all - the man has his techique right down! Good drills Si

[Alycidon]

I have recently been using a very similar technique after being quoted almost 1K inc VAT and carriage for an all singing all dancing US model shown here recently.

 

I have done a batch of 17AH cases, only about 20 so far in Butane for 7 seconds each, Cant say I saw a blue ring but as soon as the neck area started to glow a bit I stopped, I did not though quench, just let them cool naturally. Is it important to quench?, by the sound of it I should perhaps go a bit longer maybe?. I have Fire formed them and they formed fine with no splits.

 

The general consensus I found was to do them in darkness and stop as soon as they change colour.

 

A

[oaken]

I tried to anneal some .308 brass the other day only to find that there seemed to be very little warning before the brass turned to cherry red. I was using very dim artificial light so I could see any colour changes.

I will try in daylight and look for the blue marks that you describe.

I am re-enthused by your article, thankyou.

Rup

[johnnythefox]

Very interesting topic, been thinking of trying this for a few years but not bit the bullet yet, is there any chance of a photo of your set up to enlighten us more thanks

 

Cheers JTF

[Elwood]

The blue marks will not always appear, or sometimes they do but the brass will have been in the flame for to long. I found that different makes of brass all react differently.I'm not suggesting that Richness is doing it wrong, he's doing it right for his brass, but it might not work for yours.

I have no idea why some cases behave differently as I'm not a metallurgist, I can only assume that each company uses a different source of brass. I have had Winchester brass that never gave me the blue line, it gave me a faint line but certainly not a blue line, I have also had some Lapua brass do the same. The last lot of cases I did were RWS and this came out looking just like brand new Lapau, as soon as the blue line appeared past the shoulder I removed the case from the heat and blue line ran down the case wall a treat, stopping about 1/4 of the way down.

 

The only safe way to make sure you're doing it right is to use Tempilaq heat indicating liquid, watch for the paste to turn colour and watch what happens to the brass, as well as counting if you're doing them by hand.

Brass starts to anneal at 450F but it takes a long time at this temperature, so more heat is needed but over a much shorter time. This is where the information starts to get a little diluted, some people say 650F and others say 750F-800F, it's accepted that over 800F ruins the brass. I use 750F Tempilaq on the neck and 475F about 1/4 of the way down the case wall.

 

If your cases have turned bright red there is every chance that you have over cooked them, making the necks irretrievably soft and the case walls weak, this is obviously not a good situation and potentially very dangerous.

 

Quenching the cases in water has no effect on the annealing process, other than it cools the brass down quicker and prevents burnt pinkies!

 

There is a lot of information on the internet about annealing, some good and some bad, the two places I would suggest are the Snipers Hide and 6BR.com, use the search function and expect a long read.

[Guest richness]

 

 

Quenching the cases in water has no effect on the annealing process, other than it cools the brass down quicker and prevents burnt pinkies!

.

 

I agree with this.

[andybrock]

I've not tried annealing yet but I would guess the quality or make-up of the brass will have an affect on the process. If we say Lapua is at the top of the quality stakes then I assume during the annealing process the "colour" this brass produces and the time it takes to anneal will be different from a inferior quality brass due simply to the metals involved in it's original production. Also the thickness of the neck wall will also have a bearing on the time it takes etc.

 

Andy

[onehole]

Mmmmmmmmmm well! most interesting all this.I have never annealed at all and not found any reason to??? is that because all my rifles are tight necked {except 308]and operate with very small neck resizing needs?.As long as I use the correct bushing ie just putting back a 2 to 3 thou squeeze on the necks each time ,I just keep on reloading with the occasional shoulder bumping.I have not noticed any odd or inconsistent neck tension so am I let off this annealing business or is there something I am missing here,thanks Onehole.

[baldie]

Having a tight neck will make no difference. The brass will still work harden whether its fitted or not. Have a go at annealing a few and see what a difference it makes to your accuracy.It will surprise you.

[onehole]

Yeah will give it a go !! looks like a homemade "set fire to the house" type of flame throwing rig to be made then! Better have a read up on this first I guess.

Although there seems to be only positive reasons to be doing all this I am still missing the science behind why it should make a difference.Surely if I am running to tight neck dimensions and minimal movement is going on and I get good consistent feel with heads on seating what is it that happens with annealed brass necks that is going to make it so much better.

[Si-Snipe]

I tried to anneal some .308 brass the other day only to find that there seemed to be very little warning before the brass turned to cherry red. I was using very dim artificial light so I could see any colour changes.

I will try in daylight and look for the blue marks that you describe.

I am re-enthused by your article, thankyou.

Rup

 

Hey Rup

I tried annealing for the first time in bright sunlight on Sun and with perfectly polished with brasso cases for a change. It was rather difficult to monitor the flame position as the direct sunlight made it difficult to see the flame and keep it located exactly where I wanted it on the cases. Also it didn't make it easier to observe colour change.

 

Elwood you are very correct, brass from different manufacturers does vary in its effect and colour change upon annealing but I have found that universally I can see the neck become a purple/blue as it heats up to the correct temperature which as someone above mentioned varies according to composition and thickness. After a few seconds in the heat I notice a subtle browning of the brass alomst like a tarnished look (again clean brass helps with colour change observations), then it begins to darken and turn purple - this is the ideal time to start to remove from the flame. After this it turns pinky red. I have taken cases to this point and not seen any harm or negative performance from the brass but a little longer and its 'glowing' red and probably bin time.

Some types of brass look absolutely beautiful after quenching and drying but others simply look like a pinky orange around the annealed area. My .17 Rem brass after annealing looks almost dirty but I know that it was annealed correctly by the colour change when heated. So there are variations.

In my mind good light is important - I wont be using direct sunlight anymore as it made things more difficult (although still possible with intense concentration) but I do have a light in the kitchen that makes observations so easy which I will be using only from now on.

 

If anyone is wanting to practice - use some old cases up first. Take a couple of cases to where you think they need to be, then the next couple beyond that so it will help you identify when to stop without risking any useful brass.

 

I think the idea of quenching came from the worry that the heat would travel down the case too quickly and anneal the case body and using this method would prevent that. As we know top grade annealing machines don't seem to use the quenching technique but it is something I have done and continue to do so as it takes little effort to dry then for me anyway. This is not to say I may not experiment with not quenching in the future.

 

Cheers,

Si

[baldie]

Yeah will give it a go !! looks like a homemade "set fire to the house" type of flame throwing rig to be made then! Better have a read up on this first I guess.

Although there seems to be only positive reasons to be doing all this I am still missing the science behind why it should make a difference.Surely if I am running to tight neck dimensions and minimal movement is going on and I get good consistent feel with heads on seating what is it that happens with annealed brass necks that is going to make it so much better.

 

 

Every time you size your cases and seat a bullet you "work " the brass. It doesn,t matter whether you move it 1 thou or ten thou, you still work harden it. As it work hardens it loses its grip on the bullet, as it tends to spring back nearer to its unsized size. Once annealed, it tends to stay a lot closer to the sized size. It also allows the annealed brass to fireform to the chamber again like a new case.

 

You will also find if you anneal the cases you use for your stoney points, then fire them, that you wont have the shoulder/neck problems you,ve spoke of before.

[Guest richness]

Every time you size your cases and seat a bullet you "work " the brass. It doesn,t matter whether you move it 1 thou or ten thou, you still work harden it. As it work hardens it loses its grip on the bullet, as it tends to spring back nearer to its unsized size. Once annealed, it tends to stay a lot closer to the sized size. It also allows the annealed brass to fireform to the chamber again like a new case.

 

You will also find if you anneal the cases you use for your stoney points, then fire them, that you wont have the shoulder/neck problems you,ve spoke of before.

 

Yes. I few rough figures and findings for you:

When Si first started telling me his good results, I did my own test in 243. I had some brass that had been used (NS Redding die) over half a dozen times. I took a batch of it and annealed using Si's technique. I then tested it against the identical but non-annealed brass and my group at 235y HALVED.

Then, more recently, in both 17REM and 6.5x47mm we tested over the chrony the FPS spread of identical rounds, one batch annealed and one not. The spread was dramatically lower for the annealed brass.

Now you might find that with brass that hasn't been used a lot or whatever that the difference is barely detectable.....but it's these little differences that count if you ask me.

[foxing2night]

This is one reason that i like to use new brass for my comps and the old brass with a lot of firings on them i use down the fields!!!

 

You boys really deed to either get some bench-rest books and read up or go and do a few br comps and learn what people are doing to attain the accuracy levels that they need for bench-rest!!!!

 

I hear a lot of people that say they would not do br comps at 100 yrds, as there rifle shoots in the two,s and the one,s

 

Then when they turn up and the wind kills them at the diggle we never see them again???

 

Now back to your post, i have just loaded some new brass and my old brass that has had ten reloads on them,, I will take both lots down the fields and try them out at the same time

I think that there is one chap on br.com that is selling a socket to go in your drill that only allows the top part of the case to show,, then turn over a flame and then dump into a tray of water???? Sounds easy???

 

Keep up the good work fella,s

[Guest richness]

deleted by OP

[Admin 0A]

Bloody hell mate steady on. Just because we come on here and share our experiences does not mean that we ever said or mean in any way that we can turn up and spank the BR boys at their game on their hill. So don't infer, thank you very much, that we are not doing as we say we're doing. I have little interest in spending my time shooting paper and i have much less than zero interest in proving myself to anyone apart from myself. I only get a day a week for shooting and i long ago decided to dedicate that to shooting long range varmints as opposed to going the target and competition direction. Just because you don't see us there does not mean that we are talking xxx when we say we're shooting well mate. So quit it with your winks and back up telling me "what I really need to do" .

 

 

I have absolutely no doubt that f2n's comments were in good spirit.

 

Unless you're an internet-angry looking for keyboard duels, it's difficult to read them any other way.

 

Read the 3 principles below (take special note of the first one).

 

Please abide by them.

[Guest richness]

Yes i've given it some thought and i took his comments as a side-swipe like the type I've got so fed up with on the airgunbbs. I should have torn Ackley's head off for every time he said something sarcy about us "taking over the BR world with those groups", not foxingtonight's over his comments today. I'm not sure quite what he was getting at with the references to BR and i don't appreciate being told what i really need to do, but all in all it was the wrong battle to fight and I apologise to him for my venom.

[Admin 0A]

Good Man. Thank you.

 

[onehole]

Every time you size your cases and seat a bullet you "work " the brass. It doesn,t matter whether you move it 1 thou or ten thou, you still work harden it. As it work hardens it loses its grip on the bullet, as it tends to spring back nearer to its unsized size. Once annealed, it tends to stay a lot closer to the sized size. It also allows the annealed brass to fireform to the chamber again like a new case.

 

You will also find if you anneal the cases you use for your stoney points, then fire them, that you wont have the shoulder/neck problems you,ve spoke of before.

 

Baldie I have been using once fired lapua brass for doing threaded cases which I beleive are annealed at manufacture?Should I be annealing them again before firing? I didn,t have problems every time I threaded a case just sometimes you could not feel the case bottoming out or fully seating when inserting into the chamber--it was just a little too snug for hand pressure alone.The area that was always just a little fat was around and just above the case head.A light polishing and removal of a few tenths enabled the cases to fully hand insert and audibly tap the shoulder inside the chamber.

Anyway I,m gonna have a go at this annealing just to see what happens but cant get my head around why it makes such a difference.If I only need a one to two thou bullet pinch and my bushing gives me this consistently how can annealing be more beneficial???Sorry I seem to be sounding a bit of a doubter I think I better shut up till I have a go at it, no offence ment to anyone on here just thinking/talking it through, all the best Onehole.

[Si-Snipe]

Anyway I,m gonna have a go at this annealing just to see what happens but cant get my head around why it makes such a difference.If I only need a one to two thou bullet pinch and my bushing gives me this consistently how can annealing be more beneficial???Sorry I seem to be sounding a bit of a doubter I think I better shut up till I have a go at it, no offence ment to anyone on here just thinking/talking it through, all the best Onehole.

 

Hi One-hole

The factory fresh brass has a certain suppleness about it which aids with consistent hold on the bullet leading to smooth consistent release upon firing. The more times the case is shot and re-sized the less supple it becomes - which is not nessesarily a problem in itself but more the fact that the cases begin harden at slightly different rates which can be felt when seating 4th or 5th load brass that has not been annealed (all will feel firmer than new brass but some more obviously so than others). I can feel the difference between seating bullets into these cases throughout the batch if left un-annealed. The difference in pressure required to seat will show up as velocity differences. Rich and I found that annealed brass produced a slightly lower velocity than the cases which had not been annealed - this matches with the theory that with the higher seating pressures (the case mouths gripping harder on the bullets) is increasing pressure thus giving higher velocity. We know that the extreme is after the cases begin to work harden they then go the other way and spring back after the die has sized them reducing the neck tension/grip on the bullet giving lower pressures.

It through careful annealing that all the cases can be re-set to the original 'new brass' like suppleness with consistent neck tension throughout the batch. I can notice this when seating the bullets. I have just seated bullets in 45 6.5x47 cases that were annealed on Sat. I normally take out any rounds that have not seated with nice light pressure and keep them for sub 400yds. With fresh annealing there is rarely any. Out of the 45 I put 3 aside which I probably didn't need to, but I was being seriously critical (I am a bit anal with reloading) and they required an almost unoticable amount of pressure more to seat than the other 42 cases. All I can say is that if I hadn't annealed this result would have been very different for me on a 5th load batch and velocity extreme spread/vertical spread higher down range. The entire batch all seated with the ease and silky smoothness of brand new cases.

 

Good luck and let us know how you get on,

Si

[foxing2night]

Sorry boys, i did not mean to offend you lads!!!

 

I am not the best writer in the world and i think looking back at my post that it all came out wrong???

 

I will say that i am not a full blown br shooter,( I shoot factory class)But the point that i was trying to make

was that if you follow the br loading techniques and the way that they learn to read the wind, it can only make your shooting in the field a lot better,,,

 

I know from the way you boys write that you are very serious about your shooting!!! and by no means would i or did i intend to upset???

 

Like a lot of other people on this site and other br sites, i have had a lot of help over the years from people like minded as our selves, there for i am willing and have helped a lot of people that a have asked my opinion over the phone??, si snipe will comment on this i hope,,,,,

 

As i said keep up the good write ups

 

RGDS Darrel