Jeff Siewert

Can't accelerate as rapidly as a lower mass projectile.

So the volume generation rate behind the bullet is going to be lower.

That's going to cause the pressure, okay?

Increased bullet engraved length, that's going to drive the resistance, inbore resistance pressure up.

That's going to cause the peak pressure to spike.

Excuse me.

Increased bullet stiffness.

In other words, a copper, all copper versus a cup and cord jacket, that's going to bump the pressure.

Okay.

And yes, guys put, you know, particularly Barnes and Hornady on their monolithic copper offerings do put cantaloupes in there.

Basically, it's a receptacle for the displaced jacket or body material to be pushed into, and that helps reduce the engraving pressure, but it's not 100% effective in terms of getting it back to cup and core kind of levels.

Decreased free run to the start of engraving is going to boost your pressures.

Decreased internal case volume relative to a baseline

will increase your peak pressures, and obviously decreased barrel internal dimensions will drive up the resistance pressure and then also increase your peak internal pressure from combustion.

So in the block there down below, changing loaded cartridge length is complicated, okay?

Longer loaded cartridge length means more chamber volume

which would tend to give you lower pressure.

But it also comes with shorter jump to the rifling, which gives you higher pressure.

Your results are going to depend on the bullet, powder, and cartridge, okay?

So you have to – there's not a good answer for if I load my bullet out, am I going to bump the pressure up or am I going to reduce it?