So...... you have a machine screw made to fit exactly into two copper plates the bottom plate threaded. The alignment looks perfect and you immediately feel a very minor resistance. You back it out an on closer inspection you can tell that the alignment is imperceptibly off....... not enough to really measure, but just enough that you have to add a bit more torque to seat the screw home than you really should....... But it fits and it's tight.
You have a shell holder mounted at the base of your press. It's time for the resizing process. That press handle is heavy duty and the shell casing runs right up into the die, albeit with a bit of pressure you weren't quite expecting, but it goes home all the way and, upon extraction, it looks good.
Now the seating die. Your projectile is either a boattail or a very slightly rounded edge on the base. It slides down into the case mouth, and you don't really detect any real resistance, or maybe the slightest bit, so......... What has just happened?
You've (without really feeling it) just forced your shell case to align itself between the shell holder with the die....... You just did the same thing with your projectile, so.......... now both the shell case and projectile are at 90 degrees to the shell holder. Looks good....... feels straight..... roll it on the reloading bench and there's really no detectable wobble, but once it's chambered and fired, are those minute stresses that forced the shell case and projectile truly in dead alignment and absolutely concentric to the bore? The body, for sure, but what about the case neck to the base? The neck to the projectile?
With most all standard presses, absolute concentricity may or may not be absolutely true. Those minute differences only show up at real range, long distance. Everything goes into the equation when you reload. Sometimes they never show at all.
Suppose your case went up into a die that was "floating" and centered itself freely with no side pressure from the shellholder? Suppose it also went up "into" the seating die and again...... centered itself on the floating seater? Now you have a case that is reloaded with no side thrust between a fixed shell holder and die. Perfect columnation with everything in dead alignment to the case body. Those are now three variables gone from your case prep. You've also, in all likelihood, just used a Forster press.
Nit picking? Wasted time? Ask a few old benchresters, and while that's not what I'm directing you to, the fewer variables in your case prep and reloading..... the better. These are all very simple and oft overlooked aspects of reloading.
You have a shell holder mounted at the base of your press. It's time for the resizing process. That press handle is heavy duty and the shell casing runs right up into the die, albeit with a bit of pressure you weren't quite expecting, but it goes home all the way and, upon extraction, it looks good.
Now the seating die. Your projectile is either a boattail or a very slightly rounded edge on the base. It slides down into the case mouth, and you don't really detect any real resistance, or maybe the slightest bit, so......... What has just happened?
You've (without really feeling it) just forced your shell case to align itself between the shell holder with the die....... You just did the same thing with your projectile, so.......... now both the shell case and projectile are at 90 degrees to the shell holder. Looks good....... feels straight..... roll it on the reloading bench and there's really no detectable wobble, but once it's chambered and fired, are those minute stresses that forced the shell case and projectile truly in dead alignment and absolutely concentric to the bore? The body, for sure, but what about the case neck to the base? The neck to the projectile?
With most all standard presses, absolute concentricity may or may not be absolutely true. Those minute differences only show up at real range, long distance. Everything goes into the equation when you reload. Sometimes they never show at all.
Suppose your case went up into a die that was "floating" and centered itself freely with no side pressure from the shellholder? Suppose it also went up "into" the seating die and again...... centered itself on the floating seater? Now you have a case that is reloaded with no side thrust between a fixed shell holder and die. Perfect columnation with everything in dead alignment to the case body. Those are now three variables gone from your case prep. You've also, in all likelihood, just used a Forster press.
Nit picking? Wasted time? Ask a few old benchresters, and while that's not what I'm directing you to, the fewer variables in your case prep and reloading..... the better. These are all very simple and oft overlooked aspects of reloading.
