James, you asked: with a normal barrel, what would be the greatest rate of fire per minute that you could acheive before accuracy started being adversely affected?
Probably 30 or 40. But the barrel would have a shorter overall life.
In the USA, there's a service rifle match wherein competitors shoot about 24 rounds in 50 seconds at 600 yards and again at 500 yards in the first two of four stages of fire. Their super accurate match grade 7.62 NATO semiauto. There's not one bit of accuracy drop off shooting strings of fire that fast.
And I agree that MW must mean muzzle wear. Rifle barrels do not wear any significant amount whatsoever at their muzzle. Pressure's lowest there and by the time a bullets an inch full into the rifling, its perfectly sized to the bore and groove diameters and shapes ther and all the way to the muzzle anyway. Too many folks have set barrels back an inch or two and accuracy was as good as before. All they did was get rid of the bore erosion at the origin of the rifling. Bore gauges measuring barrel wear do so at the origin of the rifling; the only place that they wear out at.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master