Dunno about five second bursts. The A-10 drivers who used to visit would claim that they were only to fire two sec burst or the barrel would expand with the heat and accuracy would be similar to a Stirling SMG!! They did lose a good few knots even in a two second burst.
Saw a pair playing on STANTA as I drove home the other night.
As "Uncle Roger" used to say "Ahhh, the sweet nostalgia".
Doc C