What’s the danger with loading too little powder?
If you watch the video, the guy clearly explains why a load that’s “too light” is dangerous.
To use an over simplified analogy, it’s like a half-full gas can. One that’s half full, is far more dangerous and likely to explode than one that’s all the way full.
The “light” load doesn’t give an even steady “burn” but rather a sudden “boom.”
At least that’s the way my rather non-scientific mind understands it.
It can detonate instead of burning at a controlled rate. The ideal is having powder burn as long as it can add velocity to the bullet. If the burn peak is too early chamber pressure can go wild overcoming bullet inertia and friction. Use a good handbook, make sure the components are correct and follow directions. It takes a lot of expensive technology to do your own research and it ain’t worth it!
These are STANDARD loads in pounds per square inch.
cup just refers to the type of gauge used to measure, in most cases a crushable copper pellet of known hardness. It is placed in a hole in the chamber against the cartridge case. When the test load is fired it blows out the case wall and crushes the pellet. Measuring the amount the pellet is compressed and doing some math (actually, there are charts) gives you the pressure figure.
Even the old .38 S&W is over 14,000 psi
