The resistance to opening is in the folded area, not out in the folds themselves. Therefore, the Hartin crimp should offer as much opening resistance as a standard fold crimp.

I load 2 3/4" hulls with low pressure loads expecting to get the same performance as if I used a 2 1/2" hull. I've no interest in weeing higher up the wall with older guns.

Remember, and never forget, we are matching loads, not just hull length.