ggibson511960
Member
This is why the hobby is fun!
I enjoyed reading about this "problem". First, let me echo the compliments paid to you about your exacting measurements. Yes, you needn't be concerned about safety or accuracy, but who knows when your meticulous practices might save you? I too am a little fussy about COL, but for different reasons. I switch loads, powders, bullets, etc. a lot. I also seat and crimp in two steps to minimize bullet nose distortion. Seating stems never seem to fit bullet ogives all that well. If you incrementally seat a bullet while checking COL, the multiple trips into the ill-fitting I.D. of the seating stem will often leave a ring on the ogive as it deforms the bullet. More trips, more deformation. The effect is especially pronounced with pure lead bullets. Your photographs show a very faint ring on the bullet ogives. Very telling. In a perfect world the I.D. of the seating stem would be contour ground to exactly match the bullet nose shape. It never does. The manufacturers sell round nose and SWC stems, but they just don't contact the bullet perfectly for all the varieties out there. Check the inside of any seating stem that's seated a few hundred bullets. Full of gunk. How does the gunk stay in there? It lives in the gap between imperfect stem and bullet. It usually takes me four or five trips into the seating die to get the seating stem set, and these multiple squeezes do more bullet deformation than one push.
The effect is small, too small to affect any reasonable pistol round, but like you, I do sweat it a bit for high intensity rifle rounds.
This forum is fun. The theory above about bullet momentum during seating is entertaining reading. But far be it from me to discount theories or solutions. This hobby has a couple of hundred years of trial and error behind it, and there are still things to be discovered.
I enjoyed reading about this "problem". First, let me echo the compliments paid to you about your exacting measurements. Yes, you needn't be concerned about safety or accuracy, but who knows when your meticulous practices might save you? I too am a little fussy about COL, but for different reasons. I switch loads, powders, bullets, etc. a lot. I also seat and crimp in two steps to minimize bullet nose distortion. Seating stems never seem to fit bullet ogives all that well. If you incrementally seat a bullet while checking COL, the multiple trips into the ill-fitting I.D. of the seating stem will often leave a ring on the ogive as it deforms the bullet. More trips, more deformation. The effect is especially pronounced with pure lead bullets. Your photographs show a very faint ring on the bullet ogives. Very telling. In a perfect world the I.D. of the seating stem would be contour ground to exactly match the bullet nose shape. It never does. The manufacturers sell round nose and SWC stems, but they just don't contact the bullet perfectly for all the varieties out there. Check the inside of any seating stem that's seated a few hundred bullets. Full of gunk. How does the gunk stay in there? It lives in the gap between imperfect stem and bullet. It usually takes me four or five trips into the seating die to get the seating stem set, and these multiple squeezes do more bullet deformation than one push.
The effect is small, too small to affect any reasonable pistol round, but like you, I do sweat it a bit for high intensity rifle rounds.
This forum is fun. The theory above about bullet momentum during seating is entertaining reading. But far be it from me to discount theories or solutions. This hobby has a couple of hundred years of trial and error behind it, and there are still things to be discovered.
