The beginning of cast bullet accuracy

<url=http://www.castbulletassoc.org/view_user.php?id=7887> Bullet FIT ! This post is directed to those that think accuracy with cast bullets is a myth and to beginners having failures trying to get accuracy. I shoot cast bullets in all of the calibers I shoot, .223, 30-30, .308, 30-06, 7.62X39, 375 H&H, .458 Win Mag and .500 S&W, all rifle. Each will shoot 1 inch or less at 50 yards with a couple doing a little better. All of my loads have one thing in common that has made the difference in accuracy for me. Upon chambering a round, I can feel the cast bullet slide lightly in the chamber throat because I have taken steps to get the bullets to fit like that in every caliber that I shoot cast bullets. Actually, .458 Win Mag was the caliber that completely changed how I make an effort to get cast bullets to shoot well. Decades ago I decided to shoot cast in .458 WM because factory ammo in that caliber is so expensive that shooting the rifle was cost prohibitive but I really like my Colt Sauer Grand African in .458 WM and it has remained my favorite sporting rifle for many years. I tried several bullet designs and even honed bullet molds to get the sliding fit of bullets into the chamber with loaded rounds but still was getting 4 - 6 inch groups at 50 yards shooting the .458 WM and cast bullets with all my efforts. One day I used a kinetic bullet puller to take apart a round that I had seated the bullet too deeply into the case. I visually noticed that the area of the bullet that had been seated in the case was sized down by the brass upon seating. My .461” bullet that had the perfect fit to the chamber throat had its base and all of the bullet that was seated into the case sized down to .459"This condition of undersize bullet bases and part of the bullet body will allow gas jetting as the bullet goes down the bore when shooting and destroy accuracy. I called Lee Manufacturing's technical department and told them their .458 Win Mag Full Length Sizing Die was over sizing my brass and making my bullet bases smaller when seating cast bullets measuring .461" into my FL sized .458 WM brass. The Lee technician told me that the .458 WM actually has a slightly tapering case and is NOT a straight walled case at all. He told me that it is a common and recommended practice to back off the FL sizing for the .458 with cast bullets just to the point where the resulting case size does not cause swaging down or resizing of cast bullets to smaller than the size they were before seating. He instructed me to make dummy loads and back off the die, then pull the bullets and measure them. He said to repeat the tests till I backed the die off enough that my bullets would not be sized down and then test chambering function of the dummy load that had the right sized brass for my bullets and see if they chambered OK in my rifle. Then my common problem with cast bullets in the .458 WM would be fixed. He said that can happen in any caliber and ruin accuracy with cast bullets but other calibers will require different steps depending on the caliber and cast bullet size needed for the firearm. This all made sense to me at the time and I have learned the steps necessary for bullet fit in all my calibers. I am sure that this is a primary reason I have gotten all of my calibers to shoot well with cast bullets. Sound decisions on the use of gas checks and alloy selection to match your load level ballistic pressure are certainly important too. Load levels approaching start loads for jacketed bullets can be achieved with accuracy in many calibers using cast bullets when you make the right decisions on fit, alloy and gas checks. My favorite reference to understand alloy selection and it's relation to load pressure for plain based cast bullets is “ Modern Reloading, Second Edition” by Richard Lee. Mr. Lee presumes you already know and understand the importance of bullet fit when using cast bullets and all of his recommendations and predictions depend on bullet fit because bullet fit is the most important factor in cast bullet accuracy. Gary