The OP wants to seat the bullets without crimping and will the bullet be straight since he said also said he was getting runout. I tend to agree with Mule Deer if he is getting run out, it probably isn't caused by the seating die. It's how the brass was processed and does the brass have variations in it that are causing the run out. Wall thickness and brass length, those kind of things. The OP doesn't say if it is commercial brass or military brass and did he trim it for length ?
Yes, it could be a die that is "loose" but even if the die is loose, if the bullet is pushed straight down runout should be minimal because the die captures the nose of the bullet. That leaves the brass case itself as a variable.
kwg
