BoydAllen
Gold $$ Contributor
I have some practice cases that I cut down to a neck thickness of .0077 (measured with a .0001 neck mic.) and some new Berger Column bullets that have a pressure ring (at the base of the bullet) that measures .2437. The bushing that I sized with was a carbide .256 that is what it says it is. After measuring the length to which the bullet was pushed back to with this specific brass neck tension, barrel and bullet, I adjusted my seater so that the same bullet gave me a loaded round that was .030 shorter (than jam). At that lenghth I did a little shooting an powder tuning. (I had gotten the seating depth from a couple of excellent shooters so I thought that I would give it a try.) A couple of days later, I decided to see where that much off jam put me off of touch, as measured with my Hornady seatiing depth tool. As it turned out. I was about .023 shorter than hard thumb pressure touch. Technically the "neck tension" was .003, but with the thin necks (cut to try more chamber clearance) this is not as much bullet pull as thicker necks would have provided. Adding .030 to my seated length, and comparing it to my length when touching, the bullets had been pushed back to a seating depth that was .007 longer than the aforementioned hard thumb pressure touch. I thought that these real world numbers might give new shooters some feel for the subject. This bullet has a double radius ogive, and is based on a .790 length jacket.