fireform .200 line ?
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Farmboy method works for initial (new case measure).
When you fire your brass it will expand to chamber & springback. The last portion of case expansion, and widest part of the case will then be at a visible 'web-line'. You measure across this widest part (the web-line) perpendicular to case axis.
The web-line may not correlate to any SAAMI/reamer print datum, as your breech support and brass build will affect where the widest part ends up being.
I do a test to find 'MyMax' pressure, with culled new cases.
The object of this (for me) is to identify the point where FL sizing would be REQUIRED to recover.
I go up in load incrementally, measuring each growth, and I'll be going way up to & beyond SAAMI max unless I run into an early pressure problem.
What I'll see is growth go up, stop growing (plateau), and at some point there will be another .0005" step change. That's MyMax. For me it has so far been very near SAAMI max as per QuickLoad software.
Whether you FL size or not, you may not want pressure so high as to actually require that.
This, because FL sizing does not actually fully recover cases. The brass is moving, and it's moving away from it's strongest condition. Your primer pockets will open sooner.
When you fire your brass it will expand to chamber & springback. The last portion of case expansion, and widest part of the case will then be at a visible 'web-line'. You measure across this widest part (the web-line) perpendicular to case axis.
The web-line may not correlate to any SAAMI/reamer print datum, as your breech support and brass build will affect where the widest part ends up being.
I do a test to find 'MyMax' pressure, with culled new cases.
The object of this (for me) is to identify the point where FL sizing would be REQUIRED to recover.
I go up in load incrementally, measuring each growth, and I'll be going way up to & beyond SAAMI max unless I run into an early pressure problem.
What I'll see is growth go up, stop growing (plateau), and at some point there will be another .0005" step change. That's MyMax. For me it has so far been very near SAAMI max as per QuickLoad software.
Whether you FL size or not, you may not want pressure so high as to actually require that.
This, because FL sizing does not actually fully recover cases. The brass is moving, and it's moving away from it's strongest condition. Your primer pockets will open sooner.
Last edited:
Please check the attached tool kit. PMA retails sells the kit and some loosiesIt’s just a datum..Ya measure yer brass each firing from virgin until it stops growing.
I’ll attach a picture of the easy button/ farm boy method
J
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