Northof50,
When my bullets headspace on the bullet, it's because I seated them out far enough to do that, as the illustration shows. No relation to my crimping technique (light taper crimp). Lead bullets are too soft to cause a pressure problem in this regard. Indeed, one of the reasons the technique reduces group size is that lubricated lead bullets in this cartridge, due to the small powder space, are frequently unseated by their primers before the powder burn gets fully underway, and this means some bullets are in the lands as pressure builds, anyway, and some are only part way to the lands when the powder really gets burning. This variation in starting powder space causes ignition and velocity irregularity. Headspacing on the bullet intentionally clears it right up.
My first experiment with this was back around 1983 or '84. Using a fit up Goldcup, I was working on a gallery load using 185 grain swaged Star SWC's that someone in our bull's eye pistol league had made a bulk purchase of. Swaged bullets, being extra soft, are particularly prone to being swaged into a bore slightly off-axis. Running about 3.8 grains of Bullseye under these lit with a Federal 150 primer, at 25 yards they grouped around 2.5" off sandbags. After I started seating them out to headspace on the bullet's contact with the throat, the groups dropped to about 1.5". The same gun would shoot 200 grain hard cast SWC's into just under 1" when loaded this way and fired off bags.
The other bonus was the leading reduction. I've had my school gun (S.A. A1, fit up with a Clark barrel) shoot 3000 rounds of cast 200 grain SWC's with about 4.8 grains of Bullseye over 4 days with no cleaning and no sign of more than a few streaks of lead immediately adjacent to the lands over the first half inch of the bore ever building up. The only thing that stopped it was caking up of the powder fouling and graphite that Bullseye sprays around.
I worked this out on my own, but reading various authors over time, of course I found that others had been there before me. A number of the old bullseye shooters did this without pressure problems. (They also did things like applying heavy roll crimps below the bullet shoulder to help make this happen, but I value my brass too much to do that.)
Ammo.crafter,
The plunk of lead on a throat is slightly muted as compared to a brass case hitting the end of the chamber, but in the instance of my photo, it's on purpose. All rounds drop in freely of course. The plunk test's one shortcoming is its failure to tell you whether or not a cartridge will end up headspacing on the extractor hook. You have to look at the level of the head below the plunk to ascertain that. Since .45 Auto brass typically shortens about half a thousandth every load cycle, there will come a point where that is happening, even if it doesn't happen initially. This is another advantage of headspacing on the bullet; the length of the case isn't an issue.
