Mulligan
Silver $$ Contributor
Let me first explain my situation; I have two dasher barrels each with a different base to shoulder measurement. The used barrel has a long enough chamber that brass fired in it will not fit (bolt will not close) in the new barrel. I only have one set of dies so I have been readjusting the die a bit. The new barrel is new, as in I have not fired it yet. However I adjusted the sizing die to push the shoulder back a bit on a piece of brass fired in the old barrel to see what the difference really was (I was hoping to use the old barrel for fireforming when it where's out....oh well) it looks like 5-6 thou.
Now back to the issue at hand, I annealed a handful of clean, sized and deprimed brass from my old barrel and measured the brass for length, base to shoulder, neck diameter, and concentricity. I then resized the brass with the newly adjusted FL bushing die.
Concentricity was reduced from .001 to .0005 (1/2 thou reduction) neck diameter reduced from .2665 to .2655 (.266 bushing) (1 thou reduction) base to shoulder length reduced a lot......007 reduction!!!
So I remeasured my sized 4 times fired brass and it was where I need it to be. I pulled the bolt from my dasher, removed the firing pin and closed the bolt on a sized 4 times fired piece of brass and confirmed I could just feel the bolt close on the brass. With the sized annealed brass in the chamber the bolt closes like there is nothing there......just what I would expect.
When I adjusted the die for the 4 times fired brass to fit in my old barrel I assume there was so much "spring-back" that when the annealed brass was sized in the same die it pushed the shoulder back the .007, is this on track with what others have seen???
By the way this came about after reading the recent article about loading match grade ammo on a Dillon press with a fancy powder scale thingy. In that article the auther states he has zero runout on his brass.....so I started measuring....and annealing.
CW
Now back to the issue at hand, I annealed a handful of clean, sized and deprimed brass from my old barrel and measured the brass for length, base to shoulder, neck diameter, and concentricity. I then resized the brass with the newly adjusted FL bushing die.
Concentricity was reduced from .001 to .0005 (1/2 thou reduction) neck diameter reduced from .2665 to .2655 (.266 bushing) (1 thou reduction) base to shoulder length reduced a lot......007 reduction!!!
So I remeasured my sized 4 times fired brass and it was where I need it to be. I pulled the bolt from my dasher, removed the firing pin and closed the bolt on a sized 4 times fired piece of brass and confirmed I could just feel the bolt close on the brass. With the sized annealed brass in the chamber the bolt closes like there is nothing there......just what I would expect.
When I adjusted the die for the 4 times fired brass to fit in my old barrel I assume there was so much "spring-back" that when the annealed brass was sized in the same die it pushed the shoulder back the .007, is this on track with what others have seen???
By the way this came about after reading the recent article about loading match grade ammo on a Dillon press with a fancy powder scale thingy. In that article the auther states he has zero runout on his brass.....so I started measuring....and annealing.
CW