Thread: 6x45/6mm223 projectiles ?

Yeah so if your rifle is throated longer and you're seating the bullets out, a given charge weight should give less velocity because you're increasing the effective case capacity which is reducing pressure.

The fact you're still getting more despite your 4" shorter barrel, suggests something else (such as lot to lot variation) is going on. The chrono numbers that you're carefully observing are a red flag.