Not sure I could justify it since I’m on my seventh firing!! That’s why I was looking at the more simple options! And even then it may be easier to buy another batch after the primer pockets go!
£1400 is a lot of brass with seven firings!
Thoughts on this annealing method?
- Thread starter gixer1
- Start date
£1400 is a lot of brass with seven firings!
Stalker62
Well-Known Member
Utectok
Well-Known Member
That’s too short in the flame you need 7-8secs mostly. Use the makita drill method
Cheers Bruce…very kind offer and may take you up on that.
ThisKISS method....Spin the cases in a cordless drill, rub the neck and shoulder against a bar of soap, spin case in flame until soap goes black.
Soap goes black when it achieves 400˚ C which is the stress relief annealing temperature of 70/30 Cu/Zn cartridge brass
Annealing cases
Hi All I am about to dip my toe in the water of annealing my .243 cases. So far I have bought a blow lamp. I dont do enough reloading to invest in a dedicated annealing machine so what are the top tips for getting it right. Initial try with a crap case and my fingers didnt go too well really...www.thestalkingdirectory.co.uk
This is good advice.
If you want to anneal, get an annealer. AMP is excellent. The judgement is cost of AMP vs how much you shoot and how long cases are expected to last-hint... with the shortages likely to continue, an AMP could be a very good investment.
Not sure on this when I appear to be getting 7 firings from lapua cases. So in theory 700 rounds per 100 batch….but as Bruce kindly offered I may get them annealed.
Of course the other aspect is waste of a case on setup.Not sure on this when I appear to be getting 7 firings from lapua cases. So in theory 700 rounds per 100 batch….but as Bruce kindly offered I may get them annealed.
You should be able to get 10-12 firings from a good case such as lapua.
Suppose all depends on volume shot.
I have regularly been getting 10 or more firings from Lapua and Norma brass over the years. I only replace brass when primer pockets go slack or necks start to split. Out of interest I reloaded the same three pieces of brass 38 times and shot them at paper at 100m. Group size and point of impact remained similar throughout the experiment. I'm a deer stalker not target shooter but I do expect MOA or better and shoot all my rifles out to at least 500m and a couple out to 1000m. Maybe annealing would help me win a shooting competition but I doubt very much whether it would help me put more deer in the fridge. If it aint broke don't fix it!
Blind Pugh
Well-Known Member
Annealing is temperature - time dependent. (see attached graph)
350 - 400 C will work fine if you maintain it for at least 10 minutes. The downside is the heat will conduct down the case and anneal that as well.
In a dimly lit room you need to see dull cherry.
Watch this metallurgist guy :
350 - 400 C will work fine if you maintain it for at least 10 minutes. The downside is the heat will conduct down the case and anneal that as well.
In a dimly lit room you need to see dull cherry.
Watch this metallurgist guy :
Attachments
think the amount of time depends on the amount / mass of the item you are working with or it certainly does when hardening and tempering steel.
Ten minutes for a thin cartridge case looks to be a very long time.
Blind Pugh
Well-Known Member
That is how 25 Sharps does it. apparently
My point is that it is not properly annealed at that temperature unless it is applied for 10 or so minutes. If only applied for a few seconds it is only moving slightly up the annealing curve.
Thus, for rifle/pistol cases the heat can only be applied for a few seconds then 500-600C ie dull cherry will anneal correctly.
Off Topic
Agreed, and on the alloy...... some have to be "soaked". Allowing time for the transformation of grain structure, carbides etc in some case. Way off topic that I'm not getting into that.
I gathered that guy is referring to a full anneal and recrystallisation when I saw it some time ago. As far as I know it is unnecessary for our purposes of case longevity but may be an advantage in constancy.
The idea of taking the cases to 400˚C is to stress relief anneal them i.e. to take them through the Recovery stage without going in to Recrystallisation temperatures. Stress Relief Annealing can be done at 250˚C if you hold a tonne of 70/30 brass for an hour.
Either full or stress relief annealing will work, the case will still hold a bullet whichever you do...consistency of hardness case to case is more important than actual softness. Stress relief annealing will prevent the case necks cracking and should be closer to the pre-exisiting hardness / spring back / neck tension.
The more stressed the metal the lower the temperature that recovery or recrystallisation commences.
But there is so much potential variation of outcome depending on the grain size that came from the original rolling and annealing regime of the billet before the case makers started forming it into a case, that possibly going for a full anneal each time would reduce the variation in resulting neck tension further, but it would be along with a reduction in strength/hardness.
Hitting the same temperature each time with a 400˚ C soap tell-tale is one way to approximate stress relief annealing constancy. The time it takes to achieve that in a gas flame means that it has been going through the recovery for a few seconds once it passes 250˚C.
If the metal was very stressed / work hardened, the recovery and recrystallisation will commence at lower temperatures. But the 400˚C is a reasonable sweet spot between them.
A gas torch flame varies by 1000˚C so the position the case is held in the flame can make a difference to the time it takes to achieve 400˚C so it is still important that the every effort is made to be consistent case to case with that heating time relationship.
Copper Development Association Cartridge Brass...
Hartman paper...
One can trade graphs 'til the cows come home but one of the papers I read put some of this nuance into perspective....the Norma brass study where they were trying to achieve the same outcome on their case neck hardness in production. They use induction heating to anneal between the various stages of drawing the cases and were surprised at the variation of hardness between different places on the neck, softer towards the mouth (duh! any metalworker used to heating stuff could have told them why!**)....and everything was going as expected until one day of testing all the samples were significantly different in hardness outcomes from the previous samples...they decided that to remove that glitch that they should have only used samples of cases made from the same coil of sheet from the producer!
Alan
**it is one of the reasons that the soap tell tale is more useful to us than Tempilaq. As the soap changes colour in the run up to 400˚C you can adjust the position until you heat enough of the shoulder so that it all achieves soap black at the same point. The case mouth, with less mass than the shoulder and no attached heat sink will always get hotter faster even in an induction heater as the Norma study scientists discovered. The effect is exaggerated with a gas torch flame because that is able to lick inside the mouth and heat both surfaces at the same time.
Hartmann
The properties of cold rolled - stress relief annealed 70-30 cartridge brass
"Because of the possible commercial application of the proposed treatment of 70-30 brass, this work was undertaken. In addition, the data resulting from this work will result in a better understanding of the treatment of brass. The objectives of this work were as follows: Determine if higher...
the Norma study
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trickie
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Possibly we have the same “friend”No.
No you can't ...
Replying for friend...
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