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crimps,so important

Discussion in 'Shooting Related Threads' started by emmylou1, Feb 20, 2012.

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  1. emmylou1

    emmylou1 Active Member

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    Kevin at DR wads gave me quite a xmas present by testing my loads.My receipe was ok but crimp depth was .086 instead .055 boosting 700x to 13500 2000 over saami max. F.p.s. went to 1300...........Ive looked at crimps at the club,many are differant,I do check my drops with manual scale,so I think Im on my way to being a good loader.I bought the unloader from Gary Bulley,fine man,great tool and unloaded 44 boxes.I love the way you trapbulls push each other around,I learn so much.I was looking at high-rib trapguns more than I was Sara Evans so I bought the xt unsingle from GU.Keep the spirited threads goin..............
     
  2. Unknown1

    Unknown1 Well-Known Member

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    Might be a better idea to continue to use the data you've been using (<I>"...My receipe was ok..."</I>) but learn to measure crimp depth accurately and then learn to adjust your loader to get the depth right!<center>
    [​IMG]
    </center>

    Keller
     
  3. Gapper

    Gapper TS Member

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    I would like to know exactly what you're using in that recipe. Regards, GAP.
     
  4. hmb

    hmb Well-Known Member

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    An increase of 31 thousanths of an inch in crimp depth increases psi of shell 2000 psi, I don't think so. HMB
     
  5. Johnny

    Johnny Well-Known Member

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    emmylou1, That is what happens when you load fast powders to the max. No margin of safety. Forget about crimps "at the club" , look at some new factory shells.
     
  6. postmastertim

    postmastertim Wheels are falling off.... TS Supporters

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    Check this out what .040 will do.
     
  7. emmylou1

    emmylou1 Active Member

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    Hi guys,load was rem.gold nitro hull,209 win,DR fig.8 wad,17.5 gr.700x,chart shows psi pushing 11000........A guy like me should be working with green dot,low pressure,Im smart enough to want to learn !!
     
  8. Unknown1

    Unknown1 Well-Known Member

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    From Tom Armbrust's article regarding <I>primer substitution</i>:<blockquote>"<I>To show what happens with various crimp depths, another test was run in the Hodgdon Ballistic Laboratory using one control reload and different crimp depths. Unless otherwise listed, the data in this text was created using a standard depth of 0.055, which is a bit short of 1/16. However, some manufacturing variations exist in which case handloaders are urged to use a factory equivalent crimp depth for that particular shotshell. The test reload was checked for pressure and velocity at 0.020 increments."</I></blockquote><center><br><br>
    [​IMG]
    </center>

    Keller
     
  9. goose2

    goose2 Well-Known Member

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    How much does altitude have on pressures and velocities.
     
  10. emmylou1

    emmylou1 Active Member

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    goose 2 pushin our buttons,its fun......I dont want to mess up a 3000 dollar gun thats all............Roger
     
  11. ken a

    ken a Member

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    All this makes me wonder about 0 wad pressure, if a deep crimp makes this much difference.
     
  12. PatMiles

    PatMiles Well-Known Member

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    I learned a few important items from this thread. I went out to the shop and reset the crimp depth on my 9000. Fortunately I had the crimp depth too shallow. Reset the depth at .0050'-.0055". Measured it at the correct location also.

    Keep the nuggets of info coming.

    Pat
     
  13. hmb

    hmb Well-Known Member

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    Does this mean we can reduce the amount of powder in each shell as long as we increase the crimp depth. HMB
     
  14. cubancigar2000

    cubancigar2000 Well-Known Member

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    I am with HMB, Hogwash
     
  15. 2500 HD

    2500 HD Active Member

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    So the guns that are blowing up, the shell was crimped too deep??? Hmmmmmm
     
  16. Unknown1

    Unknown1 Well-Known Member

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    <blockquote><I>"All this makes me wonder about 0 wad pressure, if a deep crimp makes this much difference."</i></blockquote>"Wad pressure" is a hold-over the days before 1-piece plastic wads. Plastic wads don't require applied pressure to function correctly but will function just as correctly even if some pressure is applied to them by the reloading process. The crimping process will compress component stack and apply some pressure to the wad.

    "Zero wad pressure" doesn't mean that there's a lot of air above the powder; it just means that the crush section of the wad (the part that allows the wad to conform to variations in the height of the component stack) hasn't been intentionally pre-compressed by the loading process. If you cut a reload apart you'll usually find powder adhering to the underside of the over-powder cup and you'll notice that the upper half of the dissected hull (where the shot it) will spring away slightly from the bottom half of the hull. In tapered hulls this "pressure" may actually be the result of the tight fit of the over-powder cup in the base taper and not of the cup resting on the powder.

    We're talking about peak chamber pressure here. It occurs/exists for a millisecond and actually measures the amount of pressure the ignited powder charge exerts on the chamber walls before the wad and shot start to force the crimp open to escape down the barrel. The harder it is to force the crimp open the higher the peak pressure will climb during the process. The shotgun's chamber walls were designed to withstand only so much pressure. That's why a plugged barrel blows the chamber apart.

    There are lots of things that effect peak pressure that don't need to be mentioned here. Enough pressure has to be generated to assure a complete burn of that powder charge and that's a RANGE and not a specific VALUE. But too little and the burn is inconsistent; too much can damage the chamber. And that range varies from powder to powder. It's lower in the slower burning powders that are intended to move heavier shot loads at higher speeds; it's higher in fast powders designed for light shot loads that are easy to move and adequate chamber pressure has very little time to build.

    Yeah, you could probably crimp deeper if you reduced the powder charge IF you knew how much deeper you could crimp for each reduction in the powder charge before you went too far. You ain't gonna find that on a chart, And I do not want to shoot next to anybody who thinks they can guess at it and get it right.

    Keller
     
  17. JACK

    JACK Well-Known Member Supporting Vendor

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    unknown. Well then pal... you best make sure the guy shooting next to you is shooting factory loads. And tell us how often you check guys loads. We'd laugh at you in Minnesota.
     
  18. Unknown1

    Unknown1 Well-Known Member

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    <blockquote><I>"And I do not want to shoot next to anybody who thinks they can guess at it and get it right."</i></blockquote>Not to be taken literally, Bucko...poetic license and all like that. Apparently it's over your head.

    <blockquote><I>"We'd laugh at you in Minnesota."</i></blockquote>Aw... that's OK... I've heard that Minnesotans are like that when things go over their heads, too. [With apologies to any educated Minnesotans.]

    Keller
     
  19. hmb

    hmb Well-Known Member

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    Is it true that in Minnesota the most important part of reloading is that all the components fit in the hull and you get a good crimp? HMB
     
  20. shot410ga

    shot410ga Well-Known Member

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    Every book or article I've ever read said set the crimp between .030-.050.
     
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