204 from 223 cases

bsdoylebsdoyle Member Posts: 357
Is it possible to make these cases by running the ever abundent 223s through the 204 dies. Help guys. Somebody must have tried this already. I cant be the only tight wadd out there.


  • nononsensenononsense Member, Moderator Posts: 10,542 ******
    edited November -1

    Some days you bite the bear and some days the bear bites you...

    Hornady (the ammo developer) seems to have based the cartridge design on the .222 Remington Magnum. Although some of the dimensions are not exactly the same as those of the .222 Magnum, you can form .204 cases from .222 Magnum cases with a single pass through the standard resizing die and a fire-forming shot. I don't know why anyone would want to do that, though, since it's easier today for most people to get .204 cases than .222 Magnum brass.

    .204 Ruger on left/.223 Remington on the right


  • dclocodcloco Member Posts: 2,967
    edited November -1
    Yes, you can...and I did.

    You end up with a really short neck.....
  • sticks1sticks1 Member Posts: 12 ✭✭
    edited November -1
    I shoot a 6mm-.222magnum and start out with .222 mag cases. I've successfully used the .204 cases as well as .223 cases. The .223 case just ends up about 2mm shorter.
  • nononsensenononsense Member, Moderator Posts: 10,542 ******
    edited November -1

    Of course you can make cases that will fire in a .204 Ruger chamber by using the.223 Rem. case. Is it a good idea? Nope.

    There is a 0.090" difference between the two cases. Maybe that doesn't sound like much but when the shorter case is fired in the chamber with the longer neck two things happen.

    1) You get a significant build up of carbon and fouling in that empty area in front of the shorter neck. So what you ask? This build up isn't supposed to be there because it has the potential of creating higher pressures by constricting that area of the chamber. At some point in time, primers may start to crater and your bolt lift will get stiff and you'll want to know why. Well, guess why? That area is also hard to get clean and keep clean because of the type of fouling and lip of the chamber.

    2) The high velocities attribute to the .204 Ruger have come from somewhere and that somewhere is from increased pressure and hot plasma. When you shorten the neck of the case by using the .223 Rem. you essentially let that hot plasma blast away the area in your neck, leade and throat of the chamber which essentially erodes the chamber faster than if you use the right case.

    So if you want to use the .223 Rem. cases to save a little money put some of that savings away because you'll need a new barrel sooner or later.

    If you wanted to use the cheaper .223 Rem. cases, you should have opted for the .20 Tactical cartridge instead of wanting the .204 Ruger.

    Tactical 20

    The Tactical 20 was invented by Todd Kindler long before the .204 Ruger hit the market. Based on the .223 Remington parent case, the Tactical 20 is simply the .223 necked down to 20 Caliber with a 30-degree shoulder. Some versions have slightly less body taper as well--it's wise to compare reamer prints. Although the Tactical 20 has about three grains less case capacity than the .204 Ruger, it delivers very similar performance. With the right load, you can get Max velocities with 32- and 40-grainers that give up little or nothing to the .204 Ruger. Varmints probably won't know the difference. The Tactical 20 is easy to load and exceptionally accurate. Currently, Cooper Arms of Montana and Dakota Arms offer factory rifles in Tactical 20 chamberings.


    Good Luck!

  • deceedecee Member Posts: 456 ✭✭✭
    edited November -1
    My god man, You can buy them tailor made for 16 cents each!
  • 5mmgunguy5mmgunguy Member Posts: 3,853
    edited November -1
    If you are going to use 223 brass necked to 204, suggest you look at the 20 tactical or 20 practical. If you are a machinest like a friend of mine who bought a CZ 204 Ruger, then you can have some real fun. He shortened the barrel .090, and then cut off a set of 204 Ruger dies the same .090. He sizes 223 brass with the shortened 204 dies and then shoots them in the factory CZ 204 Ruger with the shortened chamber. It shoots 4000fps and 1/4 inch groups at 100yds. Why did he do it? He has tons of 223 brass and a complete machine shop and he loves to tinker with things.
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