I've been measuring AOL and jump to the lands with a Stoney Point AOL gauge and a Stoney Point Comparator from when these were Stoney Point. I followed the instructions and what I'd read and suggestions. I thought I was doing a pretty good job of it. Using the AOL tool with the modified case I arrived at a "dead length" number. I even allowed for headspace variance between the modified case and a fired case (again measured with a Stoney Point tool). I tried checking for marks from the lands after cleaning up the bullet with steel wool and sooting them up with a candle etc. I had no real joy with the last two methods, but I was pretty confident in my measurements. I then had an idea to try marking the bullet some other way to look for marks from the lands. I figured if I painted the ogive with a thin (not that it is probably possible to do it THAT thin) layer of dark nail varnish. On this basis I found that what looked like a jump was probalby a jam. The nail varnish marks easily and you can see when you are right at the jacket, or simply scraping marks in the paintwork (which is probably a really tiny bit of jump). I do realise that the nail varnish has some thickness and also that all that we really do with these tools / methods is to arrive at a starting point. The point is that if you work on what others tell you about a jump, or a jam, and how well a bullet shoots there, you may be doing something totally different from whoever measured it and is sharing this recommendation with you. And either one, or both of you may be wrong. Granted, some of you are probably really good at this, but I just thought I'd share what I found. I've now checked most of my measurements and found my "dead lengths" or "zero point" to be a slight jam. What shot best before will still shoot best now, but it's worth knowing where you are.