Bullet seating is important because it allows you to create the most optimal precision shooting results by customizing your hand loaded ammunition to tailor-fit your specific rifle. This is one of the major benefits of hand loading. Find out more about hand loading here: https://bergerbullets.com/reloading-data/
The reason that the CBTO is not listed in our loading data is because different bullet comparator tools often provide different measurement results from the same bullet. We encourage the measurement of CBTO rather than COAL whenever possible, as it will vary much less measuring from the bullet ogive than from bullet tip: https://bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf
CBTO (Cartridge Base To Ogive) is the measurement of a cartridge from the ogive of the bullet to the base of the cartridge length. This measurement is used when you are doing bullet seating depth testing: https://bergerbullets.com/vld-making-shoot/
COAL (cartridge over-all length) is the measurement of the cartridge from the tip of the bullet to the base of the cartridge. The cartridge over-all length is an important dimension to understand, especially if functioning hand loaded ammunition through a firearm magazine. https://bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf
The benefits of loading a cartridge long is that you may tailor the cartridge dimension to more closely fit a specific firearms’ dimenstions. This is a technique often used by many competitive shooters and accuracy enthusiasts to improve accuracy as part of the tuning process. https://bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-1/
CIP is the Commission Internationale Permanente that provides standardized rules for proofing weapons and ammunition for participating countries.
SAAMI stands for Sporting Arms and Ammunition Manufacturers’ Institute. SAAMI provides max pressure, cartridge dimensions, chamber dimensions and many other commercial guidelines so that both ammunition and firearm manufacturers may standardize their products.
A Hybrid Ogive blends the best aspects of the tangent and secant nose shapes into one Ogive. It starts at the bearing surface with a tangent section that will align itself more effectively when the bullet contacts the rifling. Beyond this section, the shape transitions into a secant section which is proven to be more effective in the wind. The result is a high BC bullet that is easier to tune.
A Tangent Ogive is less sensitive to seating depth but has more drag and a lower BC than a Secant Ogive of the same length.
A secant ogive is an ogive that tapers more gradually relative to its length than does the tangent ogive and touches the curve at two places, which provides a higher Ballistic Coefficient (BC) and less drag.