I don’t quite understand the concept of “bumping headspace.” When should one employ that technique rather than fully re-sizing the case.
If I start with once-fired factory brass (fired from my rifle) I know I can simply re-size the neck using my neck sizing die with bushing in place. After subsequent firings, I can continue neck sizing only, until chambering gets a little tight. (Actually, I measure the headspace using a Wilson headspace gauge rather than waiting for the chambering to get tight.) At that point:
1) I can re-size the entire case, including the case neck, using the full-length sizer die with the neck bushing inserted; or,
2) I can use the full-length sizer die simply to set back the shoulder a tad (“bumping the headspace”). - BTW, I assume that when one bumps the headspace, the neck bushing is not used… is that correct?
When the headspace increases, why would I only want to set back the shoulder and not completely re-size the case? And if I chose to employ the technique of bumping the headspace, when will I have to fully re-size that case rather than just continuing to set back its shoulder?
If I start with once-fired factory brass (fired from my rifle) I know I can simply re-size the neck using my neck sizing die with bushing in place. After subsequent firings, I can continue neck sizing only, until chambering gets a little tight. (Actually, I measure the headspace using a Wilson headspace gauge rather than waiting for the chambering to get tight.) At that point:
1) I can re-size the entire case, including the case neck, using the full-length sizer die with the neck bushing inserted; or,
2) I can use the full-length sizer die simply to set back the shoulder a tad (“bumping the headspace”). - BTW, I assume that when one bumps the headspace, the neck bushing is not used… is that correct?
When the headspace increases, why would I only want to set back the shoulder and not completely re-size the case? And if I chose to employ the technique of bumping the headspace, when will I have to fully re-size that case rather than just continuing to set back its shoulder?