i read a artical today in f/s online about reloading. not a word about head space or how it affects your loads, or how it can make your brass unusable. what is head space? this refers to the amount of the case head that sticks up in the chamber. it head space is to high you will not be able to close the chamber. if it is to low the case will hang on the extractor. if you get a loading press and dies do your self a favor and get a chamber gauge for the brass you are working. this is some 300 blkout loads i made and used to illustrate. this is what it should look like,
you can see a small step for the low end and if the brass sticks up past the top it is too high. here is a straight edge on the case gauge.![DSC04517|375x500]
so head space is the distance from the shoulder of the brass to the head and affects how the brass sits in the chamber. again if head space is to high the chamber wont close, to low and it does not fill the chamber properly and hangs on the extractor. this applys so all bottle neck cartridges. straight wall(pistol) cases head space off of the edge of the case. clearly this is grossly inadequate to fully understand head space and how important this is, but if you have never heard of it, then now you know to look! be safe loading your cases. hope this helps more then clouds up.
edit: belted magnum cases head space off of the belt not the shoulder. if you re size your brass it is easy to change the head space. i sell brass so i have had a few folks get a box of my brass, resize every piece, then complain it wont fit their gun. try the brass in your chamber before you resize it to see if it fits, if it did but you sized and now it does not, well get a case gauge and learn about head space!