6mm/220 swift?

Discussion in 'Reloading' started by huntokanogan, Mar 22, 2011.

  1. huntokanogan

    huntokanogan Well-Known Member

    Mar 7, 2011
    Just wondering if anyone has ever wildcated a 6mm bullet on a 220 swift cartridge? Is that even possible?
    I am looking for a project rifle. I want to build a 6mm caliber gun. Maybe I should just buy a .243 or 6mm rem and save the trouble. But rounds I'm considering are: 6mm/284, 6mm-06, .243 AI. Any other 6mm's I should be looking at?
  2. Trickymissfit

    Trickymissfit Well-Known Member

    Jun 11, 2010
    actually been done several times. The original case the Swift came out of was the 6mm Lee/Navy. Then there was the .240 Cobra, and maybe a couple others. Before I'd even faintly consider the three 6mm rounds you posted, I'd be looking at a 6mm Remington, or the improved version. The problem with the .284 case and the 30-06 case is that they are way overbore. You could ream the 6/.284 case about .150" short, and maybe loose 75 fps. Yet gain more than twice the barrel life. Another alternative is to use a 6mmAI reamer with a .243AI headspace gauge. You will then have a .243AI case with the better neck design of the 6mmAI. For dies you simply shorten a 6mmAI die, and run the reamer into a Forster seater sleeve. I shoot the 6/.250AI, and the difference between it and the .243AI is minimal. If speed is the issue, then a 6Vias is where you want to be (70 grain bullet at 4190 fps).