After applying gas checks and lubing a recently lot of cast bullets, I checked and found 7 of them had bases not perpendicular to the long axis of the bullet. They weren't off much but they definitly leaned when stood on their bases. Shooters "know" that this will ruin accuracy. I like to confirm that a defect has an effect on group size by shooting some. Even good "logical" assumptions are often wrong.
I loaded twenty rounds. I planned to shoot four 5 shot groups, two with bullets that looked good, one with four defective and one good bullet, and the final group with three defective and two good bullets.
The two groups with good bullets averated 1.22" at 100 yards
The two groups with a mix of bullets averaged 1.62"
This isn't enough groups to be confident, but it sure looks likte the defects did what defects are supposed to do. For additional information when I shoot groups to find what defects do I paint the noses red with a sharpie, which leaves a red rim around the bullet hole. Thus you can see where the indivigual bullets landed.
In the first defective group I found the four red rimmed holes made a 0.96" group. The "good" bullet hole was about an inch from the center of the four shot group -- what we call a flier. The three defective bullets in the second group made a 0.5" cluster, one of the good bullets landed an inch high and the other landed an inch low making the group slightly over 2".
I don't believe that bullets with bases other than 90 degrees to the long axis shoot better but this sample sure doesn't prove they shoot worse. I have been shooting comparison groups with bullets that lean for several years and I'm still not sure how much they enlarge groups -- if any. I don't have the guts to shoot them in matches yet, but I'm not sure they enlarge groups -- counter to superficial theory.
If you pay attention, cast bullet shooting will make you humble.
Has anybody checked into the effect of leaning bullets?
John
