Because it takes very little to push the bullet from the case and the pressure does not peak until the bullet engages the rifling. Using a longer throat increases the actual case capacity at peak pressure. If you use the same amount of the same powder in a larger case, pressure and velocity drops. Increasing the amount of powder will bring pressure back up to normal with an increase in velocity.
Same as loading both a 300BLK to 50,000 psi with a 150 gr bullet will produce less velocity than loading a 308 Win to 50,000 psi with 150 gr bullet



Reply With Quote
FUAC

Bookmarks