Originally Posted by statjunk
I have some fire formed brass that hasn't been put through a die yet and hasn't even had the primers removed.
I'm using a RCBS Precision Mic to measure the headspace and I'm getting a variance of 1.5-2 thousandths on the measurment between the brass.
How can that be? Shouldn't it be much tighter than that since it's fire forming to a chamber?
This condition is common for several reasons= One could be the measuring process it's self.
Measure the same piece of brass at least 4 or 5 times zeroing the instrument each time and wright down each reading, obviously if they are identical then this is not the problem.
Mose brass has slightly differences in hardness and thickness so the amount of spring back will vary plus the loads them selves are not exactly the same pressures and this can cause
the brass to measure differently.
Head space could cause this if it were poor allowing the brass to move differently under certain
If the chamber is not clean and dry (No Oil) it can allow the round to move differently each time
it is fired.
I'm sure there are other reasons that this can happen and maybe the others can add to this.
J E CUSTOM