thread revival.. So I bought this MIL to GA adapter for my C-17 headset:
https://www.marvgolden.com/mg-09-helicopter-to-g-a-headset-adapter.html
And it worked in a Cessna 182. The earphone impedance was definitely higher as I had to turn the volume all the way up to hear everything. I'm going to mod my headset and see if I can reduce it down to 300 ohms since I'll never get to fly a C-17 again anyways.