Case body springs back, same as a case neck. 0.004" resizing results in maybe 0.002" less diameter than the chamber wall.
I think JGS is recommending their resizing die reamer, used to cut a resizing die, be cut 0.004" less in diameter than the chamber reamer used to cut the rifle chamber. We talking apples to apples?
I've got several JGS chamber reamers and there excellent only other one I would consider is Manson.
I thought I stated 0.002" spring-back. Case necks are softened and annealed, so less spring-back. Case bodies aren't, so greater spring-back in my experience. And the thicker the case body, the greater the spring-back.No brass springs back 4thou, anywhere. Not even close to that.
Necks spring back 1/2thou to 3/4thou, near webs, maybe 1thou.
This is dead wrong. A case body does not spring back that much, and necks even less. 4thou of squeeze does not provide 2thou of clearance.Case body springs back, same as a case neck. 0.004" resizing results in maybe 0.002" less diameter than the chamber wall.
What fun are low end loads? Might as well shoot a cork gun, or 22 LR.stick with the reamer makers recommendations. if you don't think that brass will spring back .002 or more you need to look up all the problems the 6.5 PRC guys are having when they run upper end hunting loads. 3-4 loads on even ADG brass and they are getting stiff bolt lift and clickers. we have chamber cast the dies and they are set for .0035-.004 size at base but are only giving .001-.0015 of actual size because of spring back. leave well enough alone unless you are only running low end loads.