Since I have started reloading, I have only reloaded 1 type of bullet (Nosler CT Ballistic Silver tip). I am going to try a different type (Nosler AccuBond).
I have found that the 2 different bullets have different seating depths (COAL measured @ OGIVE, CT Ballistic tip = 3.275, AccuBond = 3.318).
To determine my seating depth I am using a fire formed case with a slightly crimped neck with a sharpie colored bullet, chambering it 3 times recording the measurements then after determining the avg. subtracting .015.
Is it common that 2 different types of bullets would have such variance in COAL? It seems odd to me.
The Hornady Comparator will produce much more accurate results. Ogive is where the straight shank of the bullet stops and the taper to the tip begins. There are always differences between various brands and weights of bullets; even the same bullets within the same box or lot, can vary. Consistent seating to the same depth, after you know which OAL is best, is what you want. You need the comparator to do this.
The Hornady Comparator will produce much more accurate results.
I better sit down with my Hornady Comparator and learn how to use it correctly. I felt months ago, when I took some measurements on specific bullets, I had it down.
After going back to remeasure, I find I have quite a "spread" in values. Apparently I have no feel and poke some into the lands and others slightly touch...there has to be a way to consistently duplicate.
Wally, I have a confession to make. I have the Hornady comparator, bought it when Stony Point made them, and did not feel it was perfect. Then I bought the Davidson base and several nose pieces from Sinclair, and found them to be superior. But many readers are not familiar with The Davidson or Sinclair, so I recommended the Hornady. I take back that statement. Look at the Davidson Seating Depth Checker. It does provide spot on measurements. Of course, there are still differences in bullet ogives. I actually seat my bullets about .005" long initially, then work them down with the Redding micrometer seater until they are exactly where I want them.
I kinda to this the redneck way. I take a sized, unprimed case and stand it up primer side down - I take a small round file and file right through the middle of the neck down to the shoulder. I then size it again. I take whatever bullet I'll be using and just get it started in the case with my fingers - then I unscrew the seating die a few turns and lower the arm to raise the bullet into the die. I screw the top of the die down until I feel tension, then a few more turns until I know it's started straight. I put it in the gun and close the bolt firmly, then carefully eject the shell and measure and record the overall length. I do this three or four times (you can pull the bullet back out of the neck with firm finger pressure) until I'm certain that the measurement is correct. I start loading by subtraction .02 from that overall measurement. It has worked well for years.