Blr243 wrote:I def flare enough to prevent shaving / reducing. Unfortunately none hit my paper target so I can’t say if they were tumbling but when at only 50 m I got Bullets goin two feet to the left and some two feet to the right something is def terribly wrong. I’ll try to get to a range or to my fathers farm so I can at least determine if they are tumbling thru a paper target
Not so much about shaving lead off the bullet, more about squeezing a soft bullet into a tight brass case, and then giving it a tight crimp, lead is a lot softer than brass - this can reduce the diameter of a soft bullet enough to cause trouble.
I've had similar results testing bullets that were undersize, not able to hit a 900mm wide panel at 50m. But I have occasionally had tumbling bullets that still shoot remarkably "accurately" at close range, say into 200mm at 50m.
I would pull one down and measure the seated bullet diameter, and push an over-size one through your barrel (well lubed) to determine the size you need. .458" or even .459" is sounding too small to me for a .458" bore with soft lead. Try .460" up to .462" if they'll chamber.
If you can recover some bullets you can look at the engraving to see if the rifling is cut cleanly or deformed by gas cutting or pushing through the rifling. I doubt they'd be pushing through if they're only around subsonic so I think size is the problem. I don't think it'd be possible to cast a 405gn bullet that would be too long to stabilise so that's not likely. Is it a really big hollow-point perhaps?