The Firing Line Forums - View Single Post

wncchester · July 8, 2010, 02:37 PM

"so, after the 1st fire, you measure, annotate the dimension of the neck diameter, but at that time,... "

All right, you ARE a bit confused! Forget the references you've seen about the headspace "datum line", which IS a diameter at about mid-shoulder, because none of that matters to us. I wasn't refering to the neck diameter at all, necks have nothing to do with headspace. Any common sizer die (FL or neck) will take care of the neck diameter as part of it's normal function, we need do nothing.

All you really need to know is that effective bottle neck "headspace" applies to the shoulder location as it's measured from the head. The various gages I listed will take that measurement very well, and from that length you can adjust the FL die up-down until the sized shoulder matches the fired location.

Read it all again with these thoughts in mind.

July 8, 2010, 02:37 PM	#12
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"so, after the 1st fire, you measure, annotate the dimension of the neck diameter, but at that time,... " All right, you ARE a bit confused! Forget the references you've seen about the headspace "datum line", which IS a diameter at about mid-shoulder, because none of that matters to us. I wasn't refering to the neck diameter at all, necks have nothing to do with headspace. Any common sizer die (FL or neck) will take care of the neck diameter as part of it's normal function, we need do nothing. All you really need to know is that effective bottle neck "headspace" applies to the shoulder location as it's measured from the head. The various gages I listed will take that measurement very well, and from that length you can adjust the FL die up-down until the sized shoulder matches the fired location. Read it all again with these thoughts in mind.