A different headspace question.

[Texas10]

Without a gage to measure your base to shoulder dimension before and after FL sizing, you really have no way of ascertaining that what you are doing is correct.

And if you are not keeping your brass trimmed to sami specs after FL sizing, you risk a chamber explosion from a pinched bullet.

For best brass life, listen to what the experts are saying (above) and only work your brass enough to fit YOUR chamber. Anything more just shortens brass life and possibly yours too if it fails catastrophically.

[RustyShackle]

A chamber should be .005 larger than than commercial ammo(ideally), the no-go gage is +0.005 over a go-gage and the field-gage is 0.009 over the go-gage, this would give commercial ammo .014 head space when fired in a chamber that a field-gage fit in.


Head space and it's effect on a cartridge: head space allows the case to stretch, with decent brass, the case will stretch that far once......, the problem comes when someone reloads the case by resizing the fired case back to minimum length, loads the case and fires it again, and repeats the procedure until the brass fatigues and separates. To avoid this, once the shoulder moves out, leave it out, use a feeler gage equal in thickness to the amount of head space to adjust the gap between the shell holder and bottom of the die with the ram up, this adjustments prevents the sizing process from moving the shoulder back.

As a rule of thumb, brass was not designed to stretch more than .006". That is the allowable given in a couple of books(IIRC). Stretch beyond that could result in case separations, and depending on the case, that could be near the case head, or further up.

GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
NO-GO: Corresponds to the maximum headspace recommended for gunsmiths chambering new firearms. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is essential for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximum in order to give a small safety margin

Hope this helps