It is easy.

Develop something.

Send a dozen or two to a military unit asking that they 'evaluate' the product.

You get a letter back saying thank you but they have no interest in your product (but probably have handed them out in the mess for a laugh).

Advertise that the product has been supplied to and used by your selected group (and you have a letter to prove it).

P.S. We always recommended a tourniquet around the neck to stop a nose bleed (it is very effective).