For bolt action rifles, I use two cleaning rods; the bullet I intend to load; some masking tape; and a set of calipers.
I plug the hole in one of the cleaning rods to make it a more accurate reading.
Close the bolt
Take the rod with the plugged hole and run it down the muzzle of the rifle.
Place a piece of masking tape around the cleaning rod right at the crown.
Next, remove the bolt and place the bullet in the chamber.
Using the other cleaning rod, hold the bullet against the lands. No need to apply a lot of pressure.
Now take the first cleaning rod and again insert it into the muzzle until it contacts the bullet; mask off your second reading.
The distance from bottom of the masking tape from first reading to the bottom of the masking tape of the second reading is the OAL. From that number I'll subtract .030 as my preferred distance from the Lands.
I usually load my '06 to an OAL of 3.250. When I measured a 150gr Sierra GK SP, the measurement came out to be 3.285. Subtract .030 and I'm at 3.255. Load up 37grs of RL17 behind the GK's and I got a group that measure .401 at 100 yards. YMMV
HaYen
