Heat the case for a specific time then measure heat with an infrared temperature measurer gun. If it's not the temp you want try next case with more or less time in the heat source. Need to measure right after removing from heat source.
Annealing: Specific Heat Question
- Thread starter nksmfamjp
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I'm rowing the same boat as you! Mine look great, like new Lapua brass. Is it done properly. ???
Mikecr
Well-Known Member
I've used lead for decades, but salt bath would work just as good and easier.
Folks need to understand that we do not want a full anneal (all life removed from brass).
Just stress relieving (process anneal) to normal & useful.
A few seconds dip into 850degF does exactly what I need.
VenatusDominus
Well-Known Member
The most important factor is that it is done consistently. Yes, brass life is one reason to anneal, but getting consistent neck tension is what you are shooting for by annealing, if of course you are aiming for long range accuracy, pun intended. So if you are getting necks/shoulders to the same temp for the same amount of time, consistently, then you should see consistent neck tension. Based on my research, you should be shooting for 1050F -1200F degrees for about 2 seconds to get a partial anneal/stress relief. Even 1300F for 30 min did not produce over annealed brass based on the studies I have seen.
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VenatusDominus
Well-Known Member
The time temperature plot for annealing cartridge brass is an "S"curve. It is far better to "over do" than "under do" as under doing places you on the middle of the "S" curve where a small difference in time/temp can have huge swings in the amount of anneal/stress relief. If you over do, you are on the flat end of the "S" curve where even relatively large temp or time changes make very little difference in amount of anneal/stress relief. You just don't want to "over do" the point of melting the brass. This is precisely what the AMP annealer does in Aztec mode, it melts a case neck to figure out how much energy is required (there is a distinct change in input energy when the brass changes from solid to liquid) and then backs off the energy slightly to define the proper anneal setting. The Eric Cortina video posted earlier in this tread illustrates the fact that over annealing is not an issue.
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Mikecr
Well-Known Member
We're not full annealing. We're restoring normal brass character.
Forget the charts for full annealing.
Forget the charts for full annealing.
VenatusDominus
Well-Known Member
I agree fully, but regardless of what you want to call it (partial anneal or stress relief), you do not want your process to leave you on the middle of the time/temp S curve where small input changes create inconsistent results. You also do not want to be on the front end of the S curve where even large changes produce essentially no changes in the brass. You need to be be on back end of the S curve where your stress relief will be most consistent, where even large input changes produce insignificant changes in stress relief. Consistency in the key factor in accurate long range shooting and reloading.
What data are you basing your 850F for a few seconds on? I am open to looking at the science behind your method. I am always interested on any scientific data on this subject.
yobuck
Well-Known Member
Just a bit of food for thought.
In 1986 a friend of mine by name of Earl Chronister shot a new 10 shot heavy gun world record group at Williamsport.
Earl didnt anneal his cases, nor did most other shooters at that time.
Now we also need to consider that the Unertl target scope Earl used would be considered inferior to pretty much all the scopes used today.
We could also discuss other things, like much better bullets, etc.
Non the less, his 1986 group is only about one inch larger than the record heavy gun group held today, and that group is now more than 10 years old.
Today i would say that most of the shooters if not all of them anneal their cases.
So my question is, what am i missing here?
For the record, i do anneal some of my cases in the hopes of them lasting a bit longer, and i do use tempilac on the neck.
In 1986 a friend of mine by name of Earl Chronister shot a new 10 shot heavy gun world record group at Williamsport.
Earl didnt anneal his cases, nor did most other shooters at that time.
Now we also need to consider that the Unertl target scope Earl used would be considered inferior to pretty much all the scopes used today.
We could also discuss other things, like much better bullets, etc.
Non the less, his 1986 group is only about one inch larger than the record heavy gun group held today, and that group is now more than 10 years old.
Today i would say that most of the shooters if not all of them anneal their cases.
So my question is, what am i missing here?
For the record, i do anneal some of my cases in the hopes of them lasting a bit longer, and i do use tempilac on the neck.
RegionRat
Well-Known Member
To keep things simple, if you try to mimic factory values for a common mil spec case, it would look pretty close to this.
The easy button is to copy the above. One could go off the reservation and develop a recipe that was slightly above or below. If you go above roughly 115, it isn't instant disaster but it gives you less margin against split necks down the road. If you go very much below 90, you can expect the other properties of the brass to come into play. Remember, I am showing you Hardness Value, but keep in mind we only use HV as a proxy for all the other properties we want. Carry On. YMMV
The easy button is to copy the above. One could go off the reservation and develop a recipe that was slightly above or below. If you go above roughly 115, it isn't instant disaster but it gives you less margin against split necks down the road. If you go very much below 90, you can expect the other properties of the brass to come into play. Remember, I am showing you Hardness Value, but keep in mind we only use HV as a proxy for all the other properties we want. Carry On. YMMV
i have it downloaded, and have read some of it. I'll get back to it. It maybe over my head, and that find too.
RegionRat
Well-Known Member
Nothing.
You have a good grasp of the issues.
If your prep process makes you happy, then I wouldn't agonize over it.
You know what works for you and what it takes to stay stocked on your brass.
Annealing is an option that a reloader can consider, not something that will stop you if you choose not to do it.
I will agree with one more concept that was being mentioned above... about staying away from inconsistency.
It takes some skills and discipline to minimize harmful variation. Dip and flame annealing are not for everyone, just like reloading isn't for everyone. One could argue that someone without patients or skills could shell out for an AMP and call it done without the homework or skills.
Annealing done properly is just a part of brass prep and prep is part of a recipe.
There are many things to balance and control in your recipe if you are being picky and want to maximize your results.
Annealing done poorly (inconsistently), can be worse than not doing it at all.
geocodyrgia
Well-Known Member
I salt bath anneal at 950* for about 6-8 seconds (whatever time it takes me to drop another case in the other hole and then come back to pick the first one out at a slow/steady pace). I've pushed about 1200 rounds of 6mm Creedmoor with loads running 2900-3200 fps on the same 100 cases of Hornady brass and not a single split neck yet.
I was annealing some 7 SAUM in the smaller case holder (the kit came with a double hole stand that will handle up to 308 and a single hole stand that handles up to 50 BMG) and the case (Bartram) got stuck for about 30 seconds or so when it expanded from the heat. Had color change to the head of the case so knew it was trash but used it to set up dies and mock up loads. The shell holder broke the rim off of that piece of brass when I tried to run it through my sizing die. I don't know all the fancy grain size hooey, but I could sure tell the difference between that one and one that didn't get stuck. Is an AMP better? Probably. Do I have the money to test it and would I ever be able to shoot the difference? I doubt it.
I was annealing some 7 SAUM in the smaller case holder (the kit came with a double hole stand that will handle up to 308 and a single hole stand that handles up to 50 BMG) and the case (Bartram) got stuck for about 30 seconds or so when it expanded from the heat. Had color change to the head of the case so knew it was trash but used it to set up dies and mock up loads. The shell holder broke the rim off of that piece of brass when I tried to run it through my sizing die. I don't know all the fancy grain size hooey, but I could sure tell the difference between that one and one that didn't get stuck. Is an AMP better? Probably. Do I have the money to test it and would I ever be able to shoot the difference? I doubt it.
Mikecr
Well-Known Member
Throw that case holder in the trash, and dip to desired level by eye/hand. Keep it simple as possible.
geocodyrgia
Well-Known Member
Actually, I really like the stand. If nothing else it prevents any kind of splash because it covers the whole top of the small lee pot I use and holds my temp probe for my pid in a good spot.
