Originally Posted by Rangefinder
Assemble a dummy round and seat the bullet very long with just enough neck tension that the bullet doesn't move freely inside the neck. Chamber it. It wil hit the lands and push back into the neck. Eject it, measure it, and then adjust your seating die to it. Then make micro adjustments deeper to keep the bullet just off the lands. THAT is your maximum OAL according to chamber. Now, max OAL according to magazine may be somewhat shorter.
Will this method work for semi-auto's or just rifles. How about the Hornaday OAL tool, is that just for rifles?