Re: Redding type S bushing size
robbor, using bushing dies with brass with uneven necks will not give you optimum accuracy. Heck using any dies with that kind of brass will deliver same results.
When I get new brass, the first thing I do is sort the brass according to neck wall thickness, before even weighing them. I've found Lapua to be very concentric and consistant. Remember that during the case drawing process a thinner portion in the neck area would extend through the length of the case which would lead to the thinner part of the case expanding more than the thicker areas during ingnition of the powder and lead to non concentric expansion of the case, starting the bullet on a line not aligned with the bore axis.
You should measure your chamber to get your chamber neck dimensions, either from the reamer used to cut the chamber, a casting of the chamber or by measuring your fired brass (get an average diameter by measuring a lot, say 50 cases ,adding all the dimensions and dividing by 50) and adding about .001" to this measurement(to allow for springback of the brass). Its not perfect, but it gives you an idea of your chamber specs.
On brass with concentric/even wall thickness you dont need to use the expander button supplied with the dies but would suggest you do use it if your case necks are not the same thickness all around.
Using brass with a thicker neck wall would "tighten"things up a little in a larger chamber, just be sure to leave enough room between the neck and chamber to allow the case to release the bullet, if not, you're on a sticky road.
Bottom line is the ideal situation is a chamber with minimum SAAMI specs,aligned with the bore axis of the barrel,using brass with no (or almost no) deviation of case wall thickness, with even neck tension, assembled in a press and die with no wobble. Check your press ram for play.
You will not have any benefits from using a redding bushing die with non uniform cases and a sloppy chamber and believing that the die alone will turn your rifle into a "tackdriver" is wrong.
Sorry for the long speech, I'll get off the soapbox now..
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