I purchased some pull down LC 12 .308 brass and the headspace measurement via Hornady comparator is 1.622". The tag attached to the SAI M1A I purchased says headspace was set to 1.632". (Fired measures 1.637") I am resizing them with some RCBS small base .308 dies and besides resizing the neck, it only barely touches the case near the head.
The stripped bolt closes on the case with no problem whatsoever and the case head has a very slight side to side movement perceptible only by feel. The way I see it, upon chambering, the cartridge will be held to the bolt face by the extractor but with pressure on the case head from the ejector. When the firing pin contacts the primer it will probably cause some forward moment to the case before ignition as there is somewhere around a .010" gap forward of the shoulder.
My questions are:
Is this condition more likely to cause stretching in the body due to the case possibly being shoved forwardbefore ignition and stretching rearward under pressure?
Does this dimension (.010") seem excessive? It seems to me that when I resize the 1.637" fired case I should at push the shoulder back to 1.630ish.
Am I reading too much into this?
The stripped bolt closes on the case with no problem whatsoever and the case head has a very slight side to side movement perceptible only by feel. The way I see it, upon chambering, the cartridge will be held to the bolt face by the extractor but with pressure on the case head from the ejector. When the firing pin contacts the primer it will probably cause some forward moment to the case before ignition as there is somewhere around a .010" gap forward of the shoulder.
My questions are:
Is this condition more likely to cause stretching in the body due to the case possibly being shoved forwardbefore ignition and stretching rearward under pressure?
Does this dimension (.010") seem excessive? It seems to me that when I resize the 1.637" fired case I should at push the shoulder back to 1.630ish.
Am I reading too much into this?