AMP annealing gone wrong?

Awesymoto

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hey guys, Recently got an AMP annealing machine for my reloading, its slick. I had a pet load for my 300 PRC that shoots pretty good, and duplicated it, same brass prep, same charge, seating depth etc… Well I got an AZTEC code of 150, and went to the range to find out it shoots pretty bad. I use a .3070 expander mandrel, and the group on the left (.2MOA ish) is the old blow torch method of annealing.

Now i’m kind of confused has anybody seen the same issues? After I grouped the two on the right top and bottom (forgive the crap pictures I took it in the sun and couldn’t see the groups / framing on my iPhone) I was scratching my head so I shot the old load and it grouped fine. I chrono’d the loads and they both were the same average and same SD.

9780AEF0-896E-46AC-AE7F-F100EFB36580.jpeg
000FFDDC-58F3-407A-AFC8-A7382FEEC79A.jpeg
 

straightshooter1

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hey guys, Recently got an AMP annealing machine for my reloading, its slick. I had a pet load for my 300 PRC that shoots pretty good, and duplicated it, same brass prep, same charge, seating depth etc… Well I got an AZTEC code of 150, and went to the range to find out it shoots pretty bad. I use a .3070 expander mandrel, and the group on the left (.2MOA ish) is the old blow torch method of annealing.

Now i’m kind of confused has anybody seen the same issues? After I grouped the two on the right top and bottom (forgive the crap pictures I took it in the sun and couldn’t see the groups / framing on my iPhone) I was scratching my head so I shot the old load and it grouped fine. I chrono’d the loads and they both were the same average and same SD.

I was just going to say, did you check the case dimensions before charging to see if they were the same as the old for might be a difference in spring back . . . particularly the amount of bump?
 

rustyinbend

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    My 300-PRC AMP code with Lapua brass is 168 ... so your 150 is in the ballpark and should be just fine. Can't imagine that the annealer is causing this, but I suppose it's possible. Frankly, I'd look elsewhere for the answer.
     
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    Awesymoto

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    I re-adjusted the die for datum off my comparator from 2.1945-2.1950“ fired to 2.1940” resized, and backed off my seating die .003-.004 for the same seating depth.
     

    Awesymoto

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    my only thought is the neck tension is less, now that it’s annealed and maybe that’s the issue? the barrel is right at 450 rounds,
    the bore looks good to me still
    CC7DE449-7573-4C65-A722-A3120B782D70.jpeg
     

    ZY100

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    For some reason, induction annealing leaves a different type of residue/oxide in the neck. Had similar results.

    I throw annealed and sized brass in the tumbler with used media for 4-5 hours and it fixed it.

    You may need to fine tune neck tension/seating as well.

    ZY
     
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    RegionRat

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    Whenever you have what you call a "good load" and you make a change and then you don't like the load.... isn't the thing to do to go back a step and see if something else was the problem?

    Nothing wrong with asking out loud in a forum, but the inevitable advice is to go back and test your process without the annealing first, and then ask how to tune your load with that change.

    Depending on if your load is "good" again, then we have a different question to begin with, and if your load is bad without the annealing, we again have a different question to begin with.
     

    918v

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    How are you sizing the case? How much is your die taking the neck down before you expand it back out?
     

    Awesymoto

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    Whenever you have what you call a "good load" and you make a change and then you don't like the load.... isn't the thing to do to go back a step and see if something else was the problem?

    Nothing wrong with asking out loud in a forum, but the inevitable advice is to go back and test your process without the annealing first, and then ask how to tune your load with that change.

    Depending on if your load is "good" again, then we have a different question to begin with, and if your load is bad without the annealing, we again have a different question to begin with.
    Good point the past 3 lots of 50 I‘ve loaded, though were the same and all around a half to 6th’s a MOA.
     

    RegionRat

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    Good point the past 3 lots of 50 I‘ve loaded, though were the same and all around a half to 6th’s a MOA.
    I would take some of the fired brass, skip the annealing, and see what you get with a quick test.

    By itself, the neck tension can cause tuning issues. There is a cycle by cycle increase in the work hardening on necks and shoulders without annealing. If your tune was so sensitive to a slight change in neck tension or friction coefficient, then you will have to decide on the re-tune with annealing, or just skip it.

    So try to keep in mind that how the combustion cycle starts when the case neck is holding the bullet is important because it sets the combustion trend but very soon after other factors take over.

    That neck is both the force and the friction holding the bullet, so you may need to re-tune the load for both reasons, the neck tension as well as the friction changes. YMMV.
     
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    CK1.0

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    Using the AMP every firing will get you brass that's crazy consistent firing to firing, it's almost like a "reset button" for cases.

    But you'll still need to come up with a specific load recipe using your freshly annealed "new" brass. Post-AMP the brass has changed from what you were using previously and is its own thing.

    The payoff comes after you find a solid load with the AMP'd stuff, then, going forward, you won't have to change shit and the stuff will shoot near the same whether 3rd firing or 13th firing (and cases will make it that far if you don't beat on them too hard).
     

    Awesymoto

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    Using the AMP every firing will get you brass that's crazy consistent firing to firing, it's almost like a "reset button" for cases.

    But you'll still need to come up with a specific load recipe using your freshly annealed "new" brass. Post-AMP the brass has changed from what you were using previously and is its own thing.

    The payoff comes after you find a solid load with the AMP'd stuff, then, going forward, you won't have to change shit and the stuff will shoot near the same whether 3rd firing or 13th firing (and cases will make it that far if you don't beat on them too hard).
    This is what I’m assuming, I may just suck it up and do another load dev.
     

    CK1.0

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    This is what I’m assuming, I may just suck it up and do another load dev.

    More than likely it's your neck tension that has changed... If it were me, I'd go to bushing a couple thou tighter than before and see what I got?

    There's no real need to worry about overworking the brass anymore with the AMP in the mix every firing.

    As an aside, I've actually been experimenting with purposely squashing my necks down more than I used to with smaller bushings before opening them back up with a mandrel... playing with the amount of engagement I want to get with the mandrel. I'm finding I can get some "free speed" without doing anything else if I want, and/or lower my SD/ES numbers by just playing with that... neat stuff.
     
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    918v

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    This is what I’m assuming, I may just suck it up and do another load dev.

    You can add powder or use a tighter bushing, or reduce the annealing setting.

    When you had the AMP analyze the case, did you input the correct bushing number? Maybe you’re over annealed the cases?
     

    918v

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    I used 031B for 300 PRC if I recall that’s what the webpage said

    Then your analysis should be good. I think the problem is bushing dies don’t size the whole neck and this reduces seating effort over standard dies. Less seating pressure, less velocity. Do you got to make that up somehow.
     
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