8,000 rounds in 4 days! Holy Molely, thats like being in a fire fight!....Well not really since no one is shooting back.

As far as Autos are concerning I have owned Remington, Browning, Ithaca, Benelli, and Beretta. All have their good points. If I could only choose one it would be the Beretta 391. Certainly shooting that many shells, your going to want a recoil friendly gas operated gun, even if it is only a 20 gauge.

Cycling that many rounds in that time frame the quality of ammunition should also be a consideration.

Good luck.