Good discussion gentlemen. As the Irishman said as he passed by two men fighting "Is this a private fight, or can anyone join in"
I have observed the same thing. Measuring every case before and after sizing and then testing the fit in the rifle chamber with the bolt stripped, one can get a good feel for the relationship between the reading from the comparator and the feel of the bolt closure. A thousandth of an inch makes a hugh difference in whether the bolt will essentially just fall or if there will be just a slight amount of drag on closure - which to me is more desirable since the bolt will drop with no resistance if the case is sized excessively. Doing this, I've found some cases in a lot will not size on the setting the die is at so these are set aside and the process is repeated again with the die adjusted down ever so slightly - I'm talking barely turning it down. Check, recheck and test fit until it is right. I like to spray the cases with an isopropyl alcohol (99%)/lanolin mixture and let the alcohol flash off in order to obtain the thinness film of lubricant possible. Go slow, dwell a few seconds in the die after the press cams over, rotate the case and repeat. I should point out that not all reloads receive this royal treatment. Only short range BR stuff. It is good practice though to check a few cases every now and then during normal reloading to make sure things are still working as expected.
Have to agree here. Spent many years around precision machining (aircraft parts). For our purposes, the tip ends of decent calipers would produce an adequate measurement of the case body at different points along the length.
Ken
In this day and age of very expensive brass I did not want to scrap any of it. So I measured each case as I zeroed in on the perfect die setting. I noticed the head to shoulder datum lengths varying about .002 depending on how much lube was used, how fast I sized and how much dwell was used at the top of the stroke.
I have observed the same thing. Measuring every case before and after sizing and then testing the fit in the rifle chamber with the bolt stripped, one can get a good feel for the relationship between the reading from the comparator and the feel of the bolt closure. A thousandth of an inch makes a hugh difference in whether the bolt will essentially just fall or if there will be just a slight amount of drag on closure - which to me is more desirable since the bolt will drop with no resistance if the case is sized excessively. Doing this, I've found some cases in a lot will not size on the setting the die is at so these are set aside and the process is repeated again with the die adjusted down ever so slightly - I'm talking barely turning it down. Check, recheck and test fit until it is right. I like to spray the cases with an isopropyl alcohol (99%)/lanolin mixture and let the alcohol flash off in order to obtain the thinness film of lubricant possible. Go slow, dwell a few seconds in the die after the press cams over, rotate the case and repeat. I should point out that not all reloads receive this royal treatment. Only short range BR stuff. It is good practice though to check a few cases every now and then during normal reloading to make sure things are still working as expected.
On an angled case or any other angled surface, a flat face mic can only measure off the high side and only then if you can manage to get the exact center inline with the center of the object you are measuring.
Have to agree here. Spent many years around precision machining (aircraft parts). For our purposes, the tip ends of decent calipers would produce an adequate measurement of the case body at different points along the length.
Ken