When the round is fired, the internal computer counts the number of rotations it makes, to calculate the distance flown. The rifle’s muzzle velocity is 210 metres a second, which is the starting point for the calculation. When the computer calculates that the round has flown the requisite distance, it issues the instruction to detonate. The explosion creates a burst of shrapnel that is lethal within a radius of several metres (exact details are classified). And the whole process takes less than five seconds.
ArsMysteriorum: From another angle, the technology of the year 40,000 AD according to Warhammer 40,000's Bolter is now available in the 21st century.I prefer my science fiction dreams to stay away from my living nightmares.