What causes higher pressure with shorter OAL.

[GuildSF4]

There are 7 physical laws, physics has three, Thermodynamics has four.

Three of the Thermodynamics laws are - you can't win; you can't break even; and you can't quit.

[SpeedQuest]

Physics...

And chemistry. At least I think it was chemistry where PV=nRT was forever burned into my memory. With nRT remaining constant, reducing V will increase P.

The equation is physics. We just let chemists use it. All science is physics or stamp collecting.

Well, if you want to quibble about it, we could just say it's all math. Try doing some physics without calculus.

As mentioned, the pressure / volume thing would be proportional but pressure tends to alter the burn rate of powders, and as this is happening, the bullet starts to move, increasing volume. Peak pressure will depend on the amount and burn rate of the powder and the movement of the bullet...making the PV equation (solving for peak pressure) quite a bit more complicated than nRT.

Good lord!! I didn't take any of those courses but I know if you throw an M80 in a 55 gal drum there is less pressure than if you throw it in a gallon paint can.

And please don't respond with a formula that says it depends on the brand of paint.

Yabbut if it's done in the woods and no one is around, does it make a sound?

Let's not get into Schrodinger's Cat at this point okay? Quantum Physics is WAAAY beyond what we need in reloading at this point.