The Spencer showed itself to be very reliable under combat conditions, with a sustainable rate-of-fire in excess of 20 rounds per minute. Compared to standard muzzle-loaders, with a rate of fire of 2–3 rounds per minute, this represented a significant tactical advantage. However, effective tactics had yet to be developed to take advantage of the higher rate of fire. Similarly, the supply chain was not well prepared enough to transport the extra ammunition. Detractors also complained that the amount of smoke produced was such that it was hard to see the enemy, which was not surprising since even the smoke produced by muzzleloaders would quickly blind whole regiments, and even divisions as if they were standing in thick fog, especially on still days.