Jeff Siewert

The cases are all designed to have a percent of ultimate strain, less than 100%.

In other words, when you're done with the firing cycle, the cartridge case remains in one piece.

OK.

And so so then we want to go look at what happens to the relative peak bolt load as a result of these different case materials.

All right.

And so over on the.

Over on the right-hand side is a graph that shows the relative fatigue life of your gun for a dirty case, which is just under 1.2.

Between the two, the purple and the dark blue line, there's a dry case in there, just about 1.25.

And then way over on the right-hand side is a red line, a lubricated case.

So when...

When you increase the bolt load, you lose fatigue life somewhere between the square and the cube of the increased load.

So if you increase the load by...

50%, it'd be 1.5, your parts life would be somewhere between 45% and 30% of the baseline load.

Is that a lot?

Yeah, it's a lot.

But if you were to, for instance, clean your, I'm sorry, lubricate your cartridge case to do the resizing job and not clean that lubricant off,

you're going to double the boat load so you're way over at 2.0 okay and and that's that's that's taken from uh medium caliber firing data where the bolts were instrumented and so we we knew how much how much the the lubricant increased increase the load um doesn't end well so kind of a word to the wise a takeaway

It would be if you're resizing your cartridge case with some sort of lubricant, and everybody does, do your best to clean off that lubricant as thoroughly as you can.

Okay.

Because you'd much rather throw away a cartridge case than throw away a bolt on a gun.