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Old May 14, 2013, 08:58 AM   #34
F. Guffey
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Join Date: July 18, 2008
Posts: 7,249
“I've always thought full length sizing was the process of reducing fired case diameters and its headspace any amount. It does not mean sizing the case back to its original dimensions when new nor back to SAAMI minimum dimensions which are typically less than what new cases are”



Then that part about “it makes good sense to me, now” The case does not have head space, the case has a length that off sets the length of the chamber, the length of the case is measured from the shoulder/datum to the head if the case. Full length sizing is full length sizing, the confusion is about full length sizing to ________________ (fill in the blank), there is full length sizing to minimum length/full length sized, Then there is the problem of assuming as in assuming the case is restored to minimum length/full length size. That brings us back to determining if the die made it to the shell holder when the ram is raised when full length sizing.

If the case is holding the die off the shell holder there will be a gap between the die and shell holder, if there is a gap between the die and shell holder there is no full length sizing back to minimum length, again, it is possible to measure the gap, a less effective method involves light passing between the die and shell holder when the ram is at the end of it’s stroke. The additional fractional turn of the die after contacting the shell holder increases the presses ability to overcome the cases resistance to sizing.

Isolating the problem: Attempt chambering the sized case before seating bullets. If the case chambers before seating bullets the problem could be caused by the seating die adjusted to crimp ‘too much’. Another set of dies? Another set of dies, for me, is a matter if choosing dies from a different drawer. Then there is the diameter thing, the case has a taper, the case is round, the round case with a taper creates varying diameters, measuring the diameter of a case anywhere along the length of the case body is doable, determining if the diameter is different at any point along the case body when compared with another case is simple, convincing someone it can be done could take a like time.

Chamber gages, I make chamber gages, for chamber gages I do not have, I have take off barrels. if the take off barrel has a bore that, for any reason, is worn out, rusted etc., it becomes a chamber gage, simply cut the chamber off then clean up in a lathe. Then it become a matter of sizing a case then dropping the case in the gage and measuring case head protrusion, point? By the time the case is sized, primed, powdered with the bullet added the reloader should know if the the reloaded round is going to chamber.

F. Guffey
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