This set includes
The Forster Ultra Micrometer Seater Die
The Ultra Micrometer Seater Die is a non-crimping style seater die that holds the bullet and case in perfect alignment while the bullet is press-fit seated.
This bushing die comes with .332, .334, and .336 diameter neck bushings.
This is a full length size die. This sets the shoulder back and sizes the body of the cartridge case in conjunction of a bushing of your choice.
Bushing selection hints
#1 Each brand of brass will have a different neck wall thickness so there is no
“Universal” diameter.
#2 Determining bushing size is a straight forward assessment. You will need to assess the neck wall thickness of the brass you are going to use. So lets say that you have some 308 Win Lapua brass. And, with a ball micrometer you have measured several cases. The average of the measurements comes out to be 0.015”. So we then multiply 0.015 by 2 = 0.030”. Then add the bullet diameter 0.308” to the neck wall measurement 0.030” to arrive at 0.338”
#3 A consensus for determining the bushing size is based on the type of rifle you are using.
A - for a bolt action rifle not using through the magazine 0.001” spring back would give you adequate neck tension. So, we deduct that 0.001 from our 0.338” measurement and arrive at a bushing size of 0.337”
B – for a bolt action feeding rounds through the magazine 0.002” spring back would give you adequate neck tension. So, we deduct that 0.002 from our 0.338” measurement and arrive at a bushing size of 0.336”
C – for a semi auto rifle feeding rounds through the magazine 0.003” spring back would give you adequate neck tension. So, we deduct that 0.003 from our 0.338” measurement and arrive at a bushing size of 0.335”
