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20 MM powder

Discussion in 'Ammunition & Reloading' started by giddyupgo55, May 26, 2010.

  1. giddyupgo55

    giddyupgo55 Vernonia Active Member

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    I have no idea what it might be used for,don't even know what number it might be on the burn scale even though I know that it burns slow. Was once told that you could fill a 7mm mag case and get top speed out of it. Any ideas as what it can be used for?
     
  2. gst264

    gst264 Independence Member

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    What's it called or how is it labeled? IMR...?
     
  3. ogre

    ogre Vancouver, WA Well-Known Member

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    I of course don't know what kind of 20mm powder you have (or whether you even have any really) so the following tidbit is for FOR INFORMATIONAL, HISTORICAL PURPOSES ONLY. Bruce Hodgdon sold salvaged 20mm powder as H4831 and had great success with it.
     
  4. gst264

    gst264 Independence Member

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    That's right...It was just in American Rifleman...I think he started with 50,000 lbs of it and stored it in a box car!
     
  5. giddyupgo55

    giddyupgo55 Vernonia Active Member

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    This powder was removed from 20mm rounds that were taken out of service for one reason or another so I have no more info then what I have been able to tell you. What issue of American Rifleman was that article in?
     
  6. motoman98

    motoman98 Gresham, OR Active Member

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    I remember buying 4831, back in the late 60's to 71 or so in paper sacks. It was taken from the cloth bags used in the 16in naval guns. Worked great in all the mag cartridges. All the load books showed 4831. No "H or IMR"...not then.
    Oh, btw, it was 79c a pound, unless you bought the whole 30lb bag, then 59c.
     
  7. giddyupgo55

    giddyupgo55 Vernonia Active Member

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    How I would like to see prices like that now. When weather get a little better I might try loading a few up and run them over the chrony. Only have a little over a pound to play with.
     
  8. jordanka16

    jordanka16 Albany, OR Active Member

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    the powder used in 20mm shells is called WC 872, it burns extremely slowly, it would most likely only work well in large bore magnum rifles. The closest powder I can think of to it is Reloader 25, and it burns slower than that.
     
  9. RAT1988

    RAT1988 WASHINGTON New Member

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    WC872 works really good in 50BMG
     
  10. giddyupgo55

    giddyupgo55 Vernonia Active Member

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    If I had a 50 I could maybe load up about 30 rounds. If anyone has a 50 and would like to try I have about 1.5 pound they could have.
     
  11. best defense

    best defense Beaverton, OR Active Member

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    You can experiment with the powder by starting out loading the largest case you have with what would be a minamum load from the slowest powder you can find. Then you can work up from there. I used to link 20MM rounds for a double barreled gatling gun while I was in the Navy. The 20MM cannons the Navy used were smooth bore, and not designed for super accuracy. They depended on volume fire to get the job done, so there was never any problem with barrel fouling the lands and grooves, and they didn't really use the guns enough to wear them out.

    If you find the powder is good for something, how about posting it here. Some of us would like to know just for fun.
     
  12. taroman

    taroman Willamette Valley Active Member

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    Smokeless powder is an excellent lawn fertilzer..
     
  13. best defense

    best defense Beaverton, OR Active Member

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    Yes, it is mostly nitrates, and will make your grass grow fast and turn it dark green.
     
  14. Partsproduction

    Partsproduction Tillamook Oregon Active Member

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    That's the first time I've ever heard that, and have personally peered down at least one 20MM barrel that is nicely rifled. I have a barrel from a GAU-8 Avenger gatling gun, 30 MM that is nicely rifled too. I see no advantage for a smooth bore unless one is shooting fin stabilized rounds like the 120MM tank rounds, and I assure you they are not renowned for any lack of accuracy.

    The CIWS gatlings that serve as a last ditch anti missile defense are rifled, so they can reach out 2.2 miles and start destroying inbound cruise missiles, which means, at the speeds they are traveling, that gives them a couple of seconds to impose some kinds of denial to their mission. I'm seriously wondering what kind of barrel you looked down as CIWS wouldn't even shoot a mile without rifling as they wouldn't have the aerodynamics to get there in tumbling flight, even at their 3600 FPS speed.

    For those interested in CIWS many may not know that they were used near Baghdad to destroy inbound rockets and mortars! The rounds used were self destructing projectiles so collateral damage could be kept to a minimum. They were tracer ammo with incendiary explosive at the end of the trace burn. Fascinating stuff! Theoretically the technology could even be used against small arms, a great expense to stop a 20 cent inbound missile. :D
     
  15. best defense

    best defense Beaverton, OR Active Member

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    The 20 MM double barreled eight shooters that I worked on were smooth bore. I understand that others may be rifled, but those were not.
     
  16. Partsproduction

    Partsproduction Tillamook Oregon Active Member

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    I'm not calling you a liar, I'm trying to make sense of what you said. I wonder if the barrels were "shot out". Do you recall what the projectiles looked like?

    Without riflings or some means to spin the shell it would have to be fin stabilized, that's not beyond possibility. Otherwise they would have needed to be spherical, ball shaped.
    Most weapons systems have at least some projectiles that are in inventory that are contact fused, which would of course mean that they would have to hit nose first, without riflings or fins that wouldn't happen.
     
  17. Partsproduction

    Partsproduction Tillamook Oregon Active Member

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    I did some more study, and it's making my head hurt. :) The CIWS Phalanx uses
    Mk 149 mod 4 ammo (GD-OTS Medium Caliber Ammunition) and clearly needs stabilization. The Phalanx has six barrels, not eight. I'm at a loss as to what you might have been looking at.
     
  18. ogre

    ogre Vancouver, WA Well-Known Member

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    It works great for roses and raspberries too! :)
     
  19. best defense

    best defense Beaverton, OR Active Member

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    As far as I know, the ammo was standard 20MM cannon ammo. Most of what we had was inherit practice projectile with an APT about every 20 rounds. We had some HEI and API, but never loaded any of that stuff. It had bronze driving band on the projectile. The guns were mounted inside a pod that hung under the belly of an aircraft, usually an F-4 Phantom. I know the 20MM cannons that we learned on in A School had rifled barrels, but these things didn't. I always thought it was odd, but I suppose they were designed for strafing, not precision air-to-air dog fights, I don't know if it really mattered very much. The ones we had were not used in any combat situation while I was there. We were never in combat.
     
  20. best defense

    best defense Beaverton, OR Active Member

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    Oh yeah, the gun had two barrels and a revolving cylinder just like a revolver handgun except it had 8 holes instead of 6 and was fed from both sides at the same time. The barrels didn't turn, just the cylinder. The barrels were mounted top and bottom.