- Joined
- Mar 25, 2013
- Messages
- 4,935
I understand that the AR-15 .223 and the NATO 5.56 round are equivalent and that the AR-10 308 and the 7.62 round are equivalent; sort of. Before you go ballistic on me (Ha) , I understand that they have different chamber pressures and one can safely fire the other but not vice versa.
My question is more basic. 0.223" does not equal 5.56mm and .308" does not equal 7.62mm. I have measured these projectiles with a caliper and the Imperial measurements are correct. How are these numbers generated and why don't they match up? What is the diameter tolerance of a bullet? Are they actually different in diameter? Please school me!
My question is more basic. 0.223" does not equal 5.56mm and .308" does not equal 7.62mm. I have measured these projectiles with a caliper and the Imperial measurements are correct. How are these numbers generated and why don't they match up? What is the diameter tolerance of a bullet? Are they actually different in diameter? Please school me!