Hulls vs Speed

I am currently reloading for and shooting a 12 gauge. I see the plastic hulls are beginning to fatigue at the corner folds and that created a question in my mind. Will the fatigued plastic be easier to open, when fired, creating less back pressure and a slower shot? The question might not be worth pursuing but I would like to know if anyone has seen data on speed vs number of times a hull has been reloaded.

Thanks in advance for your time and effort.

The short answer is yes. The impact on velocity will be less than the impact on pressure. Shotshell pressures peak early as they use "fast" powders. It has been proven that a deep crimp will increase pressure up to 2-3000 psi over a poor crimp, but the effect of velocity is on the order of 50 fps.

That higher peak pressure is not sustained as the shot column moves down the barrel.

Thanks for the info. So I’ll continue to load with confidence and use something else as an excuse when I miss.

Oh no, you can still use that one. I'm still trying "youth and inexperience" and I'll be 69 Wednesday. ;)

It is as good an excuse for missing as any!

Youth and inexperience? I'll have to try that one. I'm only 73!