bullet seating frustration

[Rustywreck]

Now that I'm starting to understand this reloading stuff a little better, I decided to buy a Redding Competition seating die.

My problems are several. I set the die up following the limited insturctions included. By trial and error I was able to get a bullet seated at the depth I desired.

After loading several rounds, I measured the bullet tip to case base length. A few were the same, but others were off by .006". Even when I used a bullet compartor to take out any inconsistancies in the bullet tip they measured differently and I don't understand why?

Also, I'm guessing the numbered markings along the barrel aren't relative to anything. That is, it can't be set to read the actual length of the cartridge. I messed around with the thing so that I could get it to read the length of the cartridge, but when I tried to make it .030" shorter, it was about .012" shorter.