The AK-47 was initially designed for ease of operation and repair by glove-wearing Soviet soldiers in Arctic conditions. The large gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle. This reliability comes at the cost of accuracy, as the looser tolerances do not allow for precision and consistency. Reflecting Soviet infantry doctrine of its time, the rifle is meant to be part of massed infantry fire, not long range engagements. The AK-47 has a service life of approximately 6,000 to 15,000 rounds.