Originally posted by Sam The ShamWell, I guess I've been corrected. 😉 Maybe what I heard was the urban legend.
You are wrong. Unstable bullets have terrible accuracy, the M-16 stabilizes them just fine.
I did check Wiki, and it mentioned that when McNamara ordered the AR15 design to be used for the new M16, that there had been some reports of bullet instability under arctic conditions. (But it would be logical to assume that they fixed the problem before production got too far along.) Also, Wiki mentioned that the M16A2 uses a faster twist rifling to allow the use of a trajectory-matched tracer round. Maybe that type of information is how the urban legend got started.
Originally posted by Mad RookI have read that a low rate of rifling twist does not stabilize a heavy bullet of a given cartridge. I do not remember which cartridge was being talked about. The problem about the rate of rifling twist is that the shooter may shoot both large and small bullet weights in any given rifle. A 30/06 Springfield in the U.S. of A. West may be used to hunt mule deer and elk. This rifle would need to stabilize 150 gr. and 180 gr. bullets. There are a lot of things going on inside and outside of a rifle barrel that effect accuracy that have nothing to do with the shooter's ability.
Correct me if I'm wrong, but it seems I remember hearing that the twist ratio of some or all of the M-16 barrels was too low, causing the aerodynamic instability of the bullets.