Back the die up a few thousandths so the fired case shoulder is bumped back only about .002".
Using the standard die setup, shoulders get bumped back a lot more. That leads to short case life because the case stretches so much with each firing. Accuracy is less, too because the case head is more out of square as it doesn't stretch back evenly all the way around; case area with the thinnest wall thickness stretches out more.
A good way to set up a full length sizing die.
1. Use a Hornady LNL or RCBS Precision Mic to measure fired but cleaned case headspace; the distance from the case head to its shoulder reference. Note the reading on the tool.
2. Full length size that case.
3. Measure its headspace again.
If it's less than.002" less, unlock the die then screw it dpwn about 1/32 turn or about 1/10th inch on its circumference then lock it in place.
If it's more than.002" less, unlock the die then unscrew it up about 1/32 turn or about 1/10th inch on its circumference then lock it in place.
4. Full length size another case.
Repeat step 3 and 4 until sized case headspace is about .002" less than fired case headspace. There'll be a couple thousandths spread across all cases, but that's fine. As long as none of them require extra force to chamber; they all should chamber without binding the bolt at all.
If you compare that "perfectly sized case to a new one, it'll have a greater headspace dimension than the new one. But each time its resized, the brass will be worked much less and last a lot more firings and resizings. You'll still need to trim it back a few thousandths once in a while to keep it from jamming its mouth into the chamber mouth when its fired.
Or..... get a set of Redding Competition shell holders then use the one that limits the die's sizing on fired cases when it's set up according to its instructions so fired case shoulders are set back only .002". They come in .002" height increments above the .125" standard
Using the standard die setup, shoulders get bumped back a lot more. That leads to short case life because the case stretches so much with each firing. Accuracy is less, too because the case head is more out of square as it doesn't stretch back evenly all the way around; case area with the thinnest wall thickness stretches out more.
A good way to set up a full length sizing die.
1. Use a Hornady LNL or RCBS Precision Mic to measure fired but cleaned case headspace; the distance from the case head to its shoulder reference. Note the reading on the tool.
2. Full length size that case.
3. Measure its headspace again.
If it's less than.002" less, unlock the die then screw it dpwn about 1/32 turn or about 1/10th inch on its circumference then lock it in place.
If it's more than.002" less, unlock the die then unscrew it up about 1/32 turn or about 1/10th inch on its circumference then lock it in place.
4. Full length size another case.
Repeat step 3 and 4 until sized case headspace is about .002" less than fired case headspace. There'll be a couple thousandths spread across all cases, but that's fine. As long as none of them require extra force to chamber; they all should chamber without binding the bolt at all.
If you compare that "perfectly sized case to a new one, it'll have a greater headspace dimension than the new one. But each time its resized, the brass will be worked much less and last a lot more firings and resizings. You'll still need to trim it back a few thousandths once in a while to keep it from jamming its mouth into the chamber mouth when its fired.
Or..... get a set of Redding Competition shell holders then use the one that limits the die's sizing on fired cases when it's set up according to its instructions so fired case shoulders are set back only .002". They come in .002" height increments above the .125" standard
