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My first Audette's; Your thoughts?

Discussion in 'Handloading and Reloading' started by berettaprofessor, Jul 13, 2019 at 5:13 PM.

  1. berettaprofessor

    berettaprofessor Member

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    Based on a question raised in this previous thread, I pursued trying an Audette's ladder with Varget as suggested.

    I loaded twenty rounds of Varget at 0.2 grain increments starting at 41.0 grains per Lyman and going to 44.8 grains (max load in Lyman was 45.7 and it is compressed at that load). The bullet is a Hornady Match 168 BTHP, shot from a Stag AR10, 18" barrel, and OAL was 2.800 as per Hodgdon 2019. The Stag is sighted to my previous "best" load, Benchmark 37.5 grains and I made one shot before the ladder with that load to make sure I was on target (Caldwell target photo). Very sunny day, temp around 87 degrees.

    I "kind of" got a ladder with velocity, but my first lesson learned is why the standing advice is to shoot at 300 yards or more so the distance between hits is increased and you can see grouping nodes better. Aim point was the black dot and the round below it was the 41.0 grain starting load. Unfortunately, I was only able to shoot at 65 yards today, and since the longest range I could have done in the vicinity was 100 yards, I just took what I had. I kept track of the individual hits and their vertical height is, for the most part, consistent with the bullet velocity (see picture).

    But, to my surprise, the velocity sometimes decreased with the next 0.2 grain increase (see chart). Does that happen often? Anyone know why? And yes, before you ask, I'm 99% sure I kept the rounds in the correct loading order. The Chronograph was a Chrony Alpha Master and I've always thought it was pretty accurate, although it didn't read two of the 20 projectiles today. Hodgdon lists the 42.0 load as 2520 fps and I chronyed it at 2543 today so that's reasonably close (although Hodgdon used a 24" barrel), and Lyman lists the 41.0 starting load at 2491, while I chronyed it at 2502. The highest load, 44.8 grains Varget, was starting to flatten the Primer a bit (see picture) so I'm happy to stop there, even though there could be another starting node around the top..

    With my novice experience, I would estimate the best accuracy node at somewhere between 43.2 to 43.6, since these rounds varied by only 9 fps maximum. Anyone else agree? Because my next is to load up a bunch of 43.4 and see how consistent it is.


    IMG_1645.JPG IMG_1646.JPG IMG_1644.JPG varget ladder.PNG
     
    Last edited: Jul 13, 2019 at 5:20 PM
  2. crestoncowboy

    crestoncowboy Member

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    I dont think I've ever had an average go down with .2 more grains. I certainly have had the velocity stay about the same with .2 grains extra. If you only shot 1 round per charge it could certainly happen. If you had loaded 5 or more rounds of each charge I'm betting that it would look better. If your extreme spread isnt 0 (its not) then that is likely the cause of the drop in velocity with more powder. If your extreme spread is 10. Then the rounds that are 9 fps could have easily been backward on the chart.

    May make no sense to anyone else (or even me if I re read my post) but it sounded pretty plausible when I was typing it. Either way I see no utility in 1 shot testing through a chrono.
     
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  3. Allen One1

    Allen One1 Member

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    Yes the velocity can go backwards even shooting 5 shot strings at each powder level. That can be a good thing as you are looking for flat spots in the velocity range. I would load 5 rounds at 43.5 and at least one and maybe a couple on each side (43.7, 43.9 & 43.3, 43.1) of it and run the test again. This time watch the velocity and the group sizes. You should be getting close to something good.
     
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  4. berettaprofessor

    berettaprofessor Member

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    Crestoncowboy, I thought that a single shot of each load was the purpose of an Audette's test...to look for velocity nodes.

    Allen One1, I'll give that a shot.
     
  5. ArchAngelCD

    ArchAngelCD Member

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    That picture does not show a flattened primer at all.

    I'm not sure how you can tell which loads are better than others when you shot them all together? I think it would be better to stick dots on the cardboard for each load so you can see which produces the best results.
     
  6. berettaprofessor

    berettaprofessor Member

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    ArchAngelCD, aren't you supposed to shoot an Audette's aiming all for the same point so you can document the change in rise with the faster loads?

    The primer was flattened in comparison with the other rounds. Not terrible yet, I agree, but flatter than it was before firing. That's a CCI 200.
     
  7. crestoncowboy

    crestoncowboy Member

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    May be. I've never done load development using this method. Not saying it's not the best method ever. I just dont know. I dont see how it could be useful given that neck tension or temperature or a host of other things could change the velocity of a single shot. Even a good extreme spread (of 4.5fps) through a great chrono would vary enough to make the 9 fps you mentioned seem irrelevant. Much less a standard chrono, which is what I use as well. I very well could be wrong though. I hope it works for you.
     
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  8. Blue68f100

    Blue68f100 Member

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    When I do test looking for nodes or small changes in velocity, I make sure that all the brass has the same volume (water), within 0.5gr or less. Using just any brass will give you some strange readings. I also hand weight the chargers to 0.02gr max deviation. This way you know the samples are as near as the same as they can be.

    It does not hurt to put them all in the same target but you need to know what load made each hole. Sometimes I will shoot individual targets and overlay them. My CE Pro has the capability to plot the data string with the phone app. It will show where the velocity flattens out, then you can go back to the raw data. The idea of shooting at longer distance is for you to be able to see the small changes. The down side is that the gun must able to produce BE accuracy and consistency. Shooting at close distance the holes should be on top of each other with minimal separation.
     
  9. ArchAngelCD

    ArchAngelCD Member

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    I don't know, you very well may be correct. I don't know what all these named tests are, I just shoot several different charges and then mess with the OAL from the best load.

    Pay no attention to what I said, sorry.
     
  10. LRDGCO

    LRDGCO Member

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    43.5 grs Varget. Done. Next. ;-)
     
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  11. WelshShooter

    WelshShooter Member

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    I echo @LRDGCO, 43.5gr is right in the middle of two similar velocities at 43.4gr and 43.6gr. Yes, it should be fine to shoot at the same poa but remember to mark your bullet holes with each powder charge. This way, you'll know if your poi always goes up with the charge or whether some charges (ie 43.4 and 43.6) will be very close together.
     
  12. berettaprofessor

    berettaprofessor Member

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    Thanks. 43.5 grains is where I'll test a few.

    How exactly does one do this? Does the inner capacity of a group of same-headstamped cases, for instance Hornady cases, really weigh enough different to measure this way? For procedure, weigh the case and then fill it with water, reweigh, and substract?
     
  13. Blue68f100

    Blue68f100 Member

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    Yes you can have over 2 gr difference in some brass lots.

    I normally do this on clean brass but fired brass will work but there will be a small error but nothing that's going to impact what you get significantly. I have special plugs for the primer pockets that use o-rings to seal.

    With a fired brass you can leave the spent primer in and fill the cartridge with water and surfactant. I normally add 1 drop of Simple green to 8 oz. to the water. May take a little more on dirty brass. Weigh the empty case, add water till it's flush with the mouth. This can be hard to see at times so good lighting is required, and the aid of a flashlight helps too. Then weight the brass when it's full of water, the difference is the internal volume weight.

    The key is that you want all the brass in the same state. New, cleaned, sized, OAL must be the same.

    This is best done on Digital scales since you can tare the empty brass then get a direct water weight.
     
  14. berettaprofessor

    berettaprofessor Member

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    I'll try it Blue68f100. Might be interesting to look at a couple of groups. Staying within 0.5 grains of case capacity you said....
     
  15. Laphroaig

    Laphroaig Member

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    You certainly have some interesting chronograph data that you could plot and analyze using the Saterlee method:



    Some other observations:

    That's an amazing amount of vertical dispersion for a test shot at only 65 yards!

    Yes, 300 yards is a better range to get results via the Audette method. But unless you have a target camera, you'll never see the holes and have to visit the target after every shot to plot the impact. I've heard of coloring the bullets with a colored sharpie that will leave some color on the target. I've never tried it and with my luck it wouldn't work anyway. My bet is that Creighton Audette had access to a range with pits and a buddy to pull his target and mark the impacts.
     
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  16. WelshShooter

    WelshShooter Member

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    It works... Sort of. I colour my bullets when working up a load and sometimes I see colour transfer to the target and sometimes I don't. Here's the best results I've had. 308 bullets travelling around 2,400fps. Here's targets for blue, red and green. I only coloured maybe the top third of an inch of the bullet which doesn't reach the ogive, so this explains why I don't see the colour up to the full diameter of the hole.

    With my 6.5x47 Lapua I don't see any colour transfer (2,900fps). Maybe velocity makes a difference?

    20190719_073543-1612x1209.jpg
    20190719_073804-1612x1209.jpg
    20190719_073748-1612x1209.jpg
     
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