[Bullet94]

I copied this from another forum.

["I believe reducing case capacity will increase pressure.

Actually, it's just the opposite, according to the Hornady manual, which has quite a discussion about it.

Three cases:
(1) Normal, nominally 0.030 JTL (Jump To Lands), safe pressure and 3500 fps (in their example);
(2) Seat more deeply, much lower pressure and 3400 fps (again their example) for the same load, due to greater expansion volume after the powder has started expanding. (The freebore serves as expansion volume, and there's more of it when the bullet is seated more deeply.)
(3) Touching the lands, velocity is (perhaps) dangerously high to achieve the 3650 fps, as the bullet did not get a running start before being slowed by the rifling."]


Could someone with QuickLOAD enter data for a common cartridge like 223 or 308 using common weight bullets (69gr / 175gr) and adjust seating depths like mag length and a couple seating depths longer without touching the lands and post the results? I’m interested in seeing if reducing case capacity increases MAX pressure or lowers MAX pressure (when seated off the lands).