Google the National Institute of Justice (NIJ) for government standards. (standard .06 IIRC
They've got more good info than you'll have time to read!
Safariland, Second Chance and other manufacturers.
I didn't fight to defend your freedom so you could vote to take away mine.
"A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself.
John Stuart Mill."