techie
04-16-2022, 05:51 PM
299122
(What looks like the slanted bottom end of the leftmost bullet is an illusion.)
When I posted about the misshapen .38 DEWC bullets (https://castboolits.gunloads.com/showthread.php?441101-Asymmetric-commercial-DEWCs) I had received from Missouri Bullet company via Midway, the consensus was that I should load them sprue end up, if at all. But one poster, Winger Ed., said to load them sprue down to look better, and thought accuracy would be about the same either way.
Before I heard from MBC that they would replace the bullets, I had loaded about 20 of them, 10 with the bad end down and 11 with it up (I miscounted while loading). I loaded them in mixed .38 SP brass, with 3.0 grains HP-38, with a very light crimp in the crimp groove. I shot groups from a rest at 25 yards from my 8-3/8" barreled S&W Model 27-2.
Here are the targets:
Wonky end up:
299123
Wonky end down:
299124
These groups are actually about the same size, and neither is satisfactory, but the one with the bad end down is clearly better. Why is that so, since so much experience seems to prove that deformation at the base is worse than deformation at the tip?
My theory is that it's the loading process. My RCBS seater stem, though marked "WC", is clearly designed for SWC bullets. It has a circular rim around a flat depression rather than a flat surface. This has never been an issue with properly made bullets, but when I seated these bullets with the pancake of lead up, flakes and slivers of lead came off almost every bullet. Originally I thought that this additional deformation near the rim of the bullet might affect its aerodynamics, but in reading the sticky on "trailing edge failure" I realized that I was getting off-center seating pressure, causing the bullets to be seated with a tilt. This seems way more plausible as a cause of the random scattering in the first group.
Any thoughts?
(What looks like the slanted bottom end of the leftmost bullet is an illusion.)
When I posted about the misshapen .38 DEWC bullets (https://castboolits.gunloads.com/showthread.php?441101-Asymmetric-commercial-DEWCs) I had received from Missouri Bullet company via Midway, the consensus was that I should load them sprue end up, if at all. But one poster, Winger Ed., said to load them sprue down to look better, and thought accuracy would be about the same either way.
Before I heard from MBC that they would replace the bullets, I had loaded about 20 of them, 10 with the bad end down and 11 with it up (I miscounted while loading). I loaded them in mixed .38 SP brass, with 3.0 grains HP-38, with a very light crimp in the crimp groove. I shot groups from a rest at 25 yards from my 8-3/8" barreled S&W Model 27-2.
Here are the targets:
Wonky end up:
299123
Wonky end down:
299124
These groups are actually about the same size, and neither is satisfactory, but the one with the bad end down is clearly better. Why is that so, since so much experience seems to prove that deformation at the base is worse than deformation at the tip?
My theory is that it's the loading process. My RCBS seater stem, though marked "WC", is clearly designed for SWC bullets. It has a circular rim around a flat depression rather than a flat surface. This has never been an issue with properly made bullets, but when I seated these bullets with the pancake of lead up, flakes and slivers of lead came off almost every bullet. Originally I thought that this additional deformation near the rim of the bullet might affect its aerodynamics, but in reading the sticky on "trailing edge failure" I realized that I was getting off-center seating pressure, causing the bullets to be seated with a tilt. This seems way more plausible as a cause of the random scattering in the first group.
Any thoughts?