Q. At what range will M193 fragment? How about M855?
Assuming true M193 or M855 ammo, velocity is the key. Velocity is dependent on barrel length and environmental conditions.
As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps. A shorter barrel imparts less velocity, and therefore the bullet has less range.
Temperature, altitude and humidity are other factors. As temperature or altitude increases, air becomes less dense and bullets travel faster. Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.
It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors. But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:
Distance to 2700 fps | 20" Barrel | 16" Barrel | 14.5" Barrel | 11.5" Barrel
M193 . . . . . . . . . . . 190-200m | 140-150m | . 95-100m . | 40-45m
M855 . . . . . . . . . . . 140-150m | 90-95m . | . 45-50m . . | 12-15m
As you can see, barrel length and ammo selection make a major impact on fragmentation range.