Ok, we are off topic a litte (sorry), but this is interesting.

I have one of the man made ferro rods that stays on the model 5 when hunting - just in case. I just tried it using a Model 10-5 (stainless) and it did work. I then compared it to the standard carbon blade which worked noticeably better. However, both did work.

Agree though: natural flint + stainless steel blade = one cold night.