> Large police and military budgets create incentives for manufacturers to innovate away from the standard and introduce "high performance" proprietary form factors.
extremely few of the calibers out there have ever seen military/LE use, and fewer of them started out with military/LE use.
If you're considering the full history of ammunition going back over 100 years, then yes. But if you limit yourself to the most commonly stocked ammo types that you would see in a store today, which would include
- 9mm
- 10mm
- .357
- 40 S&W
- 308 winmag
- 5.56
- 7.62
then no, these are most (all?) cartridges that began life with LE or military application. Even many of the less common ammo types that are still not unusual to see stocked, or seen at the range, like 300 blackout or 6.5mm Creedmore also start life as RFPs from military or LE operators.
extremely few of the calibers out there have ever seen military/LE use, and fewer of them started out with military/LE use.