Is there a tool out there to determine bullet seating depth? I always hear guys say just off the lands or touching the lands or .02 off the lands. My question is how do you get the chamber dimensions to know if your .02 off the lands? I think its called the ogive of the bullet (where it comes into contact with the lands) that determines the over all length but not sure how to get the measurement of the ogive accurately. I assume there are tools to do all this but not sure. any help??????
There are several fancy ways. I typically use the shade tree mechanic method
1) Get a fired case that will chamber in your rifle.
2) Bend a small dent in the mouth of the neck, so the case will hold a bullet.
3) Blacken the bullet with a sharpie marker.
4) Start the bullet in the case and carefully chamber it.
5) remove the case and the bullet might stay in the barrel.
6) The small dent you made in the case will have scratched the sharpie marker down to its farthest point. That depth is where the bullet is touching (or into the lands .010" or so). Write it down.
Now reload a cartridge (can be a dummy if you want) and make it about .015 shorter than the number you got in #6 above. before you chamber it, blacken it with a candle. Candle black will wipe off at the lightest touch, so when you carefully chamber it, you will see if you touch the lands at all. If you don't touch, then you can make it a little longer, blacken it again etc etc. Until you have a depth that you feel is just touching the lands. Write it down.
There are a number of tools for measuring the ogive, I like the Hornady tool that attaches to you calipers.
The distance to the lands will grow as you shoot and erode the throat of your rifle.
Anyway, That should give you an idea of how it can be done with very few tools. It takes an hour or so to get a measurement you can trust, but it's not that bad.
Here is the tool I use to measure base to ogive length.
Lock-N-Load Bullet Comparator Basic Set 6 Inserts
AJ