Above is a 5 shot group shot at 350 yards using powder coated (PC) cast bullets. The bullets are a 200 gr bore rider and were cast using a Lee C309-200-R. They were fired in a rifle chambered for .308 Win. The group was not the best or the worst of the day, but it proves that PC bullets can be accurate. It is also worth noting that I did not go to the trouble of weighing and sorting the bullets prior to loading. The powder that was used for PC was obtained from fellow forum member Smokes.
I hope the pictures (below) help explain the procedure used to create the bullets. I believe the fact that over 60% of the bullet fits tightly in line with the bore’s axis when fired helps to stabilize the bullet and contributes to its inherent accuracy. Additionally, powder coated bullets can be easily sized so that the bore rider portion of bullets with this type of geometry can be custom fit to specific rifles.
For any bullet to perform well, the base has to be square to the longitudinal axis. As cast, the bases are seldom perfect due to spru and deformities on bottom corners. This makes seating gas checks perfectly square almost impossible. To overcome this, a custom gas check seating die was constructed.
The gas check seater was made to insure that the base of the gas check is seated squarely with the longitudinal axis of the bullet. It consists of a die and a ram. A hammer blow to the ram insures that the bullet is seated squarely and that there is full contact between the gas check and the base of the bullet. Any spru imperfections are flattened and full contact between the bullet and the lip on the gas check is acheived. Experiments showed that applying the gas checks before PC slightly improves accuracy. After seating the gas check, the bullet was run through a Lee .310 sizing die to lock the gas checks in place before powder coating.
After the gas checks were seated and sized, Smokes powder was applied using a single application of the “shake and bake” method. Bullets were placed vertically on a layer of oven liner using a pair of large tweezers. They were baked for 25 minutes, and then they were dropped into ice water to cool.
The base or driving band portion of the bullet was re-sized to .310 inches, which is .002 over the measured diameter of the barrels groves. To accomplish this, the bullets were lubricated using a spray bottle containing a mixture of anhydrous lanolin and ISO-HEET. The bullets were then run through a polished Lee push-through sizer.
The next step is neck sizing the bore rider portion of bullet so that it just fits the bore. In my case, the bore measured out at the classic .300 inch, or at least as close as I could measure.
In order to control the length of the bore rider portion of the bullet that is sized, I had to make a die bushing holder. The die can be adjusted in the press similar to a normal case sizing die. One of the biggest advantages of this approach is that the bushings are cheap, and they can be easily interchanged.
For the actual sizing I used a reground Redding neck sizing bushing. As received, the bushings will not work; they remove portions of the powder coating and push back excess lead. After being reground and polished, they do not remove any of the powder coating and the lead will actually be extruded uniformly as long as gross amounts are not relocated. On the 200 gr Lee bullets, the length does increases .014 inches. An ejector punch rides in the die housing and is used to drive the bullet out with a leather mallet.
Correctly sized and ready to load bullet
Continued part 2