Ned Ludd
Silver $$ Contributor
The real question with virgin brass is how much effort to put into working up a load that will probably need to be tweaked or possibly even changed markedly once the brass has been fire-formed. How much effort should be put into working up a load in virgin brass that will probably change as soon as it has been fired? Only the individual can decide for themselves.
Having said that, it is absolutely possible to develop a load in quality virgin brass that shoots very, very well, if a little care is taken while preparing the brass. I generally do the following steps with virgin brass:
1) check and uniform flash holes
2) FL re-size with a bushing die
a) with a properly set die, this will not bump the shoulder of virgin brass at all
b) I use a bushing ~.001" smaller than the one I would use if the bushing die were the only sizing step
3) open necks with a mandrel that is .0015" under bullet diameter for ~.002" neck tension/interference fit
4) clean
5) trim/chamfer
Basically, this approach involves sizing down the necks by about .001" more than would normally be used/needed to yield ~.002" neck tension. In other words, you need a bushing about .001" smaller than might normally be used as the sole sizing step to yield .002" neck tension by itself, largely because there can be a range of neck diameters in virgin brass straight out of the box. Thus, the subsequent mandrel step will do work on all the case necks, not just some, opening them up slightly from the inside to a [more] uniform diameter for loading. If one desires a little more or less neck tension than ~.002", the diameter of the bushing and/or mandrel used can be selected appropriately based on the observation that a mandrel of ~.0015" under bullet diameter will yield pretty close to .002" neck tension when combined with the appropriate bushing diameter as described above due to spring-back of the brass.
Having said that, it is absolutely possible to develop a load in quality virgin brass that shoots very, very well, if a little care is taken while preparing the brass. I generally do the following steps with virgin brass:
1) check and uniform flash holes
2) FL re-size with a bushing die
a) with a properly set die, this will not bump the shoulder of virgin brass at all
b) I use a bushing ~.001" smaller than the one I would use if the bushing die were the only sizing step
3) open necks with a mandrel that is .0015" under bullet diameter for ~.002" neck tension/interference fit
4) clean
5) trim/chamfer
Basically, this approach involves sizing down the necks by about .001" more than would normally be used/needed to yield ~.002" neck tension. In other words, you need a bushing about .001" smaller than might normally be used as the sole sizing step to yield .002" neck tension by itself, largely because there can be a range of neck diameters in virgin brass straight out of the box. Thus, the subsequent mandrel step will do work on all the case necks, not just some, opening them up slightly from the inside to a [more] uniform diameter for loading. If one desires a little more or less neck tension than ~.002", the diameter of the bushing and/or mandrel used can be selected appropriately based on the observation that a mandrel of ~.0015" under bullet diameter will yield pretty close to .002" neck tension when combined with the appropriate bushing diameter as described above due to spring-back of the brass.
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