Thread: See separation?

Originally Posted by Longranger

Some actions allow easier determination of headspace than others.....the key is to strip the bolt so there is no spring resistance and insert a fire-formed case...there should be some resistance to closing the bolt. If that is so then measure with a headspace comparator and record that dimension.....this is a critical dimension to which all other re-sized cases must comply. Re-size to this dimension with the same comparator and test in the chamber.....if the bolt is harder to close than with a fire-formed case then reduce the dimension fractionally with your die until the bolt is closing without effort.....please note re-sizing will initially increase the length of your brass so it should be tight before you get the correct dimension.

My trick is to set the die clamp ring higher than needed, mark it and slowly lower it using the mark as an index until your brass has reached the correct dims....the clamp ring in this scenario is only a stop to ensure you don't go too far down....! In some instances it may be necessary to remove approx 0.025" or more from the base of the die to ensure the shell holder doesn't bottom out on the die before the case is properly sized....!

You also need to know what the internal dimension of those necks are before expanding them again......I would not like to see the die reducing the ID anymore than 0.281"...get another die if that is the result because they appear to be seriously over-worked. Good luck...!

Is it possible @Longranger that the cases that had neck separation are actually too long and the end of the neck is tight against the start of the lands ??. I made this mistake after stripping the bolt to find correct reference headspace as you describe and got so carried away I forgot to check case length until I got funny results with headspace. Just wonder what would happen if an overlength case was fired ?