Roger N
Another approach you might take, and I know we will hear some arguement about it, is to seat the bullet just a few thousandths short of where you want to be the final overall length. Then adjust the final length by using a roll crimp and crimp until the bullet is squeezed back to the correct overall length.
The only thing you need to be really sure of is that before starting the crimp the mouth of the case is somewhere over the crimp groove. This may work with a Lee factory crimp die if the bullet will stay within .005 or so of the final length, but will probably not work well. A roll crimp die is probably best.
This operation serves two functions, setting overall length quite precisely, and assuring that the crimp is really tight and actually bearing on the bullet providing resistance to initial movement.
This is admittedly one of those things which "works for me", that's all I can say to qualify it. What got me started doing it this way was the latter, assuring a crimp bearing tightly on the bullet and holding it back against the initial primer pressure pulse. The primer can not only push the bullet through a loose crimp, but, in some circumstances actually push the bullet well down the barrel causing other potential problems.
Another approach you might take, and I know we will hear some arguement about it, is to seat the bullet just a few thousandths short of where you want to be the final overall length. Then adjust the final length by using a roll crimp and crimp until the bullet is squeezed back to the correct overall length.
The only thing you need to be really sure of is that before starting the crimp the mouth of the case is somewhere over the crimp groove. This may work with a Lee factory crimp die if the bullet will stay within .005 or so of the final length, but will probably not work well. A roll crimp die is probably best.
This operation serves two functions, setting overall length quite precisely, and assuring that the crimp is really tight and actually bearing on the bullet providing resistance to initial movement.
This is admittedly one of those things which "works for me", that's all I can say to qualify it. What got me started doing it this way was the latter, assuring a crimp bearing tightly on the bullet and holding it back against the initial primer pressure pulse. The primer can not only push the bullet through a loose crimp, but, in some circumstances actually push the bullet well down the barrel causing other potential problems.
