boltman - very informative images, thanks for the post. It's one thing to know the numbers in your head, but another to actually see them marked on the bullets. Based on the amount of shank in the neck, the only bullet I would even consider trying to use in the .169 fb chamber from that panel would be the 80 VLD. Certainly, it may be that some (or all) of them could be tested and tuned at seating depths much greater than about .015" to .025" off the lands where my loads usually end up, thereby putting more shank in the case neck. Unfortunately, I'm much too lazy to go to all that effort
.
I have never had any issues whatsoever using the Hornady OAL gauge (Stoney Point tool). The question you have to ask is, how do you know which approach is actually giving you the most accurate measurement? Not so easy for most people to answer definitively and both approaches have potential sources of error. What I can tell you is that for dummy rounds made using measurements taken with the Hornady tool at "touching", I do not see land engravement if I chamber them. However, I can see engravement if I seat them as little as .004" (estimated from the "touching" measurement) into the lands. So the measurements are probably at least that close. With the Hornady tool, how hard you push on the set rod can make a big difference in the measurement you get. If you push the bullet in even with medium force, it is very easy to engrave it, meaning you actually pushed it into the lands. I find that a very light touch is all it takes and it is very easy with a little practice to feel the when the bullet just touches the lands. If you feel like the Hornady OAL gauge might be giving you readings that are in the neighborhood of .008" long, simply check the bullet ogive for land engravement. That much should be visible to the naked eye. If you're unsure, just color up the outside of the bullet ogive with a Sharpie, which makes it much easier to see engraving marks.
In the bigger picture of things, it really doesn't matter much in the case of bullets jumped 5-10 thousandths (or more), because we use measurements such as "distance to the lands" primarily in a relative way only. As long as my measurement isn't so far off that a bullet I thought was seated .010"
off the lands was actually .005" or more
into the lands, it's not going to cause any big problems. Measurements taken with the Hornady OAL gauge should easily be much, much closer than that. What matters most is that whatever seating depth I find shoots optimally in actual loading/testing of rounds is
reproducible. Even though you might set up a seating depth test series based on measurements made with your Hornady OAL gauge, you will ultimately be measuring and test firing actual loaded rounds. The potential for error in measurements of those should be very small, and you will directly observe their behavior on the target. So you will know the CBTO measurement (seating depth) with good accuracy of the rounds that shot best, and will also be able to reproduce that measurement consistently.
The most critical thing I have found with the 90 VLDs and the Rem ISSF chamber with regard to use of the Hornady OAL gauge is the diameter of the freebore. If you look carefully at the reamer print, the freebore is only 0.0002" over bullet diameter. In my rifle, the 90s always get hung up slightly in the tight freebore on the way in, well before reaching "touching". So it takes a much finer touch to push them in without accidentally jamming them into the lands.
Seating depth photo
