As said, it has been done and some have "paid" a bunch.
The front of a military jacket is quite thick and you won't get much expansion anyway. File a groove down the side and look at jacket thickness.
BUT what can happen, with both ends open... hole at the base and a hole at the front... load may blow the core out of the jacket leaving the jacket in the barrel. Next shot rings the barrel. As a rule the shooter does not get hurt, but the barrel is junk. It may or may not be visible, but usually you can feel it. Accuracy goes down. Value of the gun drops. A box of hunting ammo with soft points is a whole lot cheaper. ALOT. luck.