Editing Dewoitine D.520 (section)

===Armament===
[[File:Dewoitine 520 ON040.jpg|thumb|A D.520 after crash landing]]
Production-standard armament consisted of a {{cvt|20|mm|3}} HS.404, which had an ammunition capacity of 60 rounds, firing through the propeller hub, and four belt-fed MAC 1934 M39 {{cvt|7.5|mm|3}} machine guns in the wings, with 675 rounds per gun.<ref name="Danel and Cuny 1966, p. 249"/> The MAC 1934 machine guns had a high [[rate of fire]] of 1,200 rounds per minute (rpm), while the HS.404 had an effective rate of fire of 600 rpm and was accurate up to {{cvt|500|m}}; the ammunition capacity meant that the machine guns could be fired for a total of 30 seconds, while the cannon had ten seconds' worth of ammunition.

In combat, the MS.406 had only a pair of {{cvt|7.5|mm|3}} machine guns and was, therefore, at a disadvantage when the HS.404 had used up its ammunition, while a D.520 could continue to fight effectively because it had four fast-firing machine guns (over 80 rounds/sec), with 20-plus seconds of ammunition still available. The D.520 had provisions for two BE33 "illuminating bombs", useful for nocturnal interception missions, but these were seldom used because French fighters rarely flew nighttime missions.<ref>Danel and Cuny 1966, p. 236.</ref>