Here's what I did: Cut a slit down the neck of a FL sized case with a Dremel tool. Insert a bullet into the neck just far enough to stay in place. Carefully chamber, then carefully extract. Measure COL with calipers. I found the slit down the neck allows enough tension to maintin the bullet's position after chambering, but still allows removal of the bullet without tools.
I took two such measurements for three different bullets of each different type, and found no more than .002" difference between measurements of a single bullet, and no more than .004" between different bullets of the same type.
Now, if I want to be .050" from the rifling, I seat to a COL .050" less than the max COL as determined above.
Does this sound OK to you all?
Don
I personally like to use the REAL OLD "Flat Tip Jag on a Cleaning Rod" method, because it eliminates the possibility of the Bullet "snagging" on the lands and giving a Clintonesque reading(aka Lying to you). And, I've done it so long, it is just second nature to me.
Two BIG pieces of advice though, first be sure to use the "EXACT SAME BULLET" you did your measurements with to set-up the Seating Die. The reason for this is because the actual length of the bullets in a box vary a good bit. So, if you use any other bullet, you WILL NOT be setting the Seating Depth properly.
Second, once you get that Bullet Seated at the correct Depth, snug-up the Seating Stem jam nut, remove the Seating Die from the press, and then measure the "Overall Length of the Seating Die" from the bottom to the top of the Seating Stem. Write this measurement on the exact box of bullets your measurement bullet came from.
Now, as long as the cartridge will fit in the magazine, forget all about COL and go by OSDL(Overall Seating Die Length).
The "variance" in the bullets is 95% from the Ogive to the Tip. So, when you switch to OSDL, you are working from the Ogive and you will get consistent seating throughout that box. Plus, you can adjust the Seating Depth easily where ever you want it with no set the Seating Die, measure, reset the Die, etc.
Just be sure to measure the "First" bullet out of every new box, convert to OSDL and you will get better accuracy in the long run.
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Good hunting and clean 1-shot kills, Hot Core