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Thread: How often do you anneal your brass

  1. #31
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    I don't like to waist the brass so i anneal every time. I still shoot them well over 30 times, maybe close to 50 by now. At long range, if you don't it's easy to see. Bullet release has to be the same if you want to shoot small and be consistent...... jim

  2. #32
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    Quote Originally Posted by Damon View Post
    Keith - that is counter to the data I've seen. The ASM and ASTM specs for C26000 cartridge brass show that annealed brass is closer to 45ksi in ultimate strength, while work hardened samples can get as high as 95ksi, and that both yield and ultimate strength increase with work hardening. Am I missing something? I purposefully left some of the numbers out because not all brass is made from the same alloy, and used C26000 data because I had it. Of course, eventually the work hardening stops (She can't take no more cap'n!) - but the brass is quite brittle at that point, and it's in that state that you see split necks.
    Damon,
    Oops, I have my numbers wrong. Olin cartridge brass alloy 260 yield stress varies from 10 ksi to 33 ksi annealed and from 21 ksi to 93 ksi roll tempered (work hardened). Tensile strength varies from 45 - 61 ksi annealed and 49 - 104 ksi rolled.

    The same concept still applies, though. If you run the calculations, what you find is that the deformation becomes more elastic and less plastic with each sizing and firing. For BR spec chambers, strains are less than 1%, which even for the most work-hardened case means that the material never reaches the tensile stress at which failure occurs. For instance for a 30 BR with 0.002" clearance, the strain is 0.65%. Failure thus eventually occurs due to cyclic fatigue, which may take thousands of cycles. Or a defect in the material.

    It takes at least about 0.004" clearance for the brass to reach tensile stress (split necks) for the most work-hardened state. But this large a clearance is, in general, not BR quality.

    Cheers,
    Keith

  3. #33
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    Quote Originally Posted by mks View Post
    Damon,
    Oops, I have my numbers wrong. Olin cartridge brass alloy 260 yield stress varies from 10 ksi to 33 ksi annealed and from 21 ksi to 93 ksi roll tempered (work hardened). Tensile strength varies from 45 - 61 ksi annealed and 49 - 104 ksi rolled.

    The same concept still applies, though. If you run the calculations, what you find is that the deformation becomes more elastic and less plastic with each sizing and firing. For BR spec chambers, strains are less than 1%, which even for the most work-hardened case means that the material never reaches the tensile stress at which failure occurs. For instance for a 30 BR with 0.002" clearance, the strain is 0.65%. Failure thus eventually occurs due to cyclic fatigue, which may take thousands of cycles. Or a defect in the material.

    It takes at least about 0.004" clearance for the brass to reach tensile stress (split necks) for the most work-hardened state. But this large a clearance is, in general, not BR quality.

    Cheers,
    Keith
    No disagreement there. I may go revise my article to make it more clear - what you write here is exactly what I meant to convey. I was also thinking about writing up a quick study on neck clearances and neck stress/strain. Sounds like you've run the numbers already. I'm still on the fence as to whether or not I think annealing matters for BR. I think it can help keep your cases together for sloppier chambers (i.e. non-BR), but I don't shoot enough benchrest to have a strong opinion based on experience, as I mostly shoot High Power, and even then I try to run clearances on the tighter side.

  4. #34
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    I think you would be better to use a strain gage and see what it takes to seat a bullet. same case 10 times with out annealing and do the same thing annealed. You will get a better idea why you anneal Every time you size the numbers go up, without annealing........ jim

  5. #35
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    Quote Originally Posted by jim1K View Post
    I think you would be better to use a strain gage and see what it takes to seat a bullet. same case 10 times with out annealing and do the same thing annealed. You will get a better idea why you anneal Every time you size the numbers go up, without annealing........ jim
    Jim,
    Not necessarily. If you are using low neck tension, the seating force decreases as you size more times without annealing. In fact, it can decrease so much that the bullet just drops into the case.

    Keith

  6. #36
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    I don't mean the force with different size bushings but use the same and size and seat a bullet. when i do ten compare the the difference in seating pressure and do each one not annealed and annealed. If you are annealing right you will find the seating pressure is more uniform and the non annealed will gain seating pressure with each sizing and seating. You must fire it and size each time with both sets. I anneal every time and cases with 30+ loadings take the same amount of pressure as they did new. I use to do it every 3rd loading and i watched the seating pressure rise on the second and the 3rd loading. At long range i can tell by the amount of vertical in the group, i try to hold 2 lb. in seating pressure, i'm using .002 neck tension and that gives me like 26-28 pounds of seating force for the most. Now if you resize and load again it will increase on some case to over 30-35 range, and the next firing some even get more. Like i said at long range it is really easy to see...... jim

  7. #37
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    Question

    Quote Originally Posted by jim1K View Post
    I don't mean the force with different size bushings but use the same and size and seat a bullet. when i do ten compare the the difference in seating pressure and do each one not annealed and annealed. If you are annealing right you will find the seating pressure is more uniform and the non annealed will gain seating pressure with each sizing and seating. You must fire it and size each time with both sets. I anneal every time and cases with 30+ loadings take the same amount of pressure as they did new. I use to do it every 3rd loading and i watched the seating pressure rise on the second and the 3rd loading. At long range i can tell by the amount of vertical in the group, i try to hold 2 lb. in seating pressure, i'm using .002 neck tension and that gives me like 26-28 pounds of seating force for the most. Now if you resize and load again it will increase on some case to over 30-35 range, and the next firing some even get more. Like i said at long range it is really easy to see...... jim
    Jim, What are you using to measure the amount of pressure required to seat a bullet ?

    Dick

  8. #38
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    Quote Originally Posted by jim1K View Post
    I don't mean the force with different size bushings but use the same and size and seat a bullet. when i do ten compare the the difference in seating pressure and do each one not annealed and annealed. If you are annealing right you will find the seating pressure is more uniform and the non annealed will gain seating pressure with each sizing and seating. You must fire it and size each time with both sets. I anneal every time and cases with 30+ loadings take the same amount of pressure as they did new. I use to do it every 3rd loading and i watched the seating pressure rise on the second and the 3rd loading. At long range i can tell by the amount of vertical in the group, i try to hold 2 lb. in seating pressure, i'm using .002 neck tension and that gives me like 26-28 pounds of seating force for the most. Now if you resize and load again it will increase on some case to over 30-35 range, and the next firing some even get more. Like i said at long range it is really easy to see...... jim
    Jim,
    Yes, that is what I thought you meant. With the first several sizings, seating force increases. But when you get to a certain point in work-hardening, the neck recovers elastically after sizing so much that seating force decreases relative to the first sizing. 0.002 neck tension is probably low enough to see this, so my guess is that you are annealing before you get to the reduced seating force phase.

    If annealing works for you, great. All I am saying is that there are two ways to get to consistent neck tension. I don't know which is best, because I haven't quantitatively compared them.

    Cheers,
    Keith
    Last edited by mks; 06-10-2013 at 09:00 PM.

  9. #39
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    Keith -- It's been my experience that whether bullet pull is greater or less with more firings depend on the kind of die used. If you use a bushing die only, you get less tension after about 4-5 firings. If you use a die with an expander, it gets greater.

    Of course, it is the spring back of the brass at play, so which way things go depends on whether the last operation was a "constriction" or an "expansion."

    As far a long range consistency goes, I always "oversized" .001 or so -- however much it took so that the last operation was with a specially sized, polished mandrel, to take the the i.d of the neck UP to desired size. Didn't have to anneal, and the final bullet pull was extremely even. Nor was I moving the brass all that much.

  10. #40
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    My two cents, I've been playing with Annealing by doing it every time and have found that at a point my tight groups seem to open up because I us a tight neck to start with, so I'm going to try annealing once and see how many times I go before I start to feel the difference in neck tension or the groups get bigger. I think there maybe a happy medium that when the brass starts to work harden after so many firings its time to anneal again, hope this make sense because mine seem to work best after about the third firing!


    Joe Salt

  11. #41
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    Reading are done with two, one was a strain gage 10-50 lb. and the K&M force indicator. We used the real strain gage to get a to see if the numbers on the K&M were close to accurate and they were. I was looking for numbers for reference the amount of force required to seat a bullet, and try to get uniform sets for record rounds. It also shows the amount of force it increased from one firing to the second and the third. This was only done on the 6mm cases....... jim

  12. #42
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    jim1K,
    Did you use your strain gage load cell to do a pull test on the cases after you seated your bullets. I would like to be able to make a slug to load of just copper, the dia. would be the same as the bullet dia. Make the slug about 2in. long with a hole near one end so you can do put test also. I worked R&D Eng. with Boeing, Titusville, Fl.
    john
    Mims, Fl.

  13. #43
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    Did a load cell to do a seating test, I couldn't do a pull test. I wanted data for loading after the the strain gage testing was over and i was back with the stuff i have to load with..... jim

  14. #44
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    Quote Originally Posted by Charles E View Post
    ... Didn't have to anneal, and the final bullet pull was extremely even. ...
    Charles,
    Thanks for sharing your experience with not annealing. To add to this, I don't think I am the only score shooter who has sized 40-50+ times without annealing. After the first dozen or so, and after a bushing adjustment or two, seating force remains very uniform without any extra processing. This behavior is predicted by the equations, and is validated by real shooting data.

    Thanks,
    Keith

  15. #45
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    This thread is very funny. I had an email from one of the top shooters. Said it was discussed at the Super Shoot. It was considered a joke by the top shooters at the Super Shoot.
    If any of you want to be a top shooter, spend your time and money at the range.

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