I'm hand loading Lyman 358156 boolits for my 357 Magnum Smith & Wesson 686-2. The OAL spec is 1.590". Following the Hornady seating die instructions, I backed off the crimp and seated two boolits at 1.590". Next I backed out the seater and then reset the die to apply a roll crimp. Then reset the seater to touch the bullet. When I'm done, the OAL is now about 1.566". What am I doing wrong?