In the U.S., the best way to go to market as a defense startup is the SBIR program (or similar small business R&D set aside). The second best option is to subcontract to friends at larger defense contractors. Both are excellent pathways.
I know a number of folks who get or have gotten SBIRs. The rules of the game requiring knowing them well in advance of showing up because timing matters.
It's a mixed bag. You obviously need to know the rules, but they aren't too complicated. SBIR topics are released several times a year in huge batches. Pretty much every branch of government has topics out for proposal, military, health, education, etc. Topics vary in specificity from "Pitch us anything" to "We want this very complicated component that does XYZ, is this exact size, and meets these exact specifications and performance values". The latter are usually pretty clearly intended for a specific company who either already makes or is already researching that component, but they're using the SBIR fund for money so they can't just pick them specifically. I can't prove it, but those just seem to be someone that knows someone important and managed to get a very specific SBIR written for their thing. Some are also clearly written by people who have no idea what they want. I used to work for a start up that did a lot of SBIRs while trying to get off the ground. They'd write like 10-15 proposals per year and maybe get approved for 1-4.
That is about the right hit rate based on my experience, too. I co-wrote a lot of SBIR proposals, and our success rate was about 10-20%. But it’s worth it! $100k for the Phase 1, and close to $1 million if you are successful and you are invited to submit for the Phase 2.
