We have been down this road again and again. It is a fact beyond dispute that the fastest cycling shotguns are the Winchester SX2 (FN SLP) and SX3. The official record is 12 shots in 1.442 seconds with a SX3.
True. There are 3 or 4 of the top 3Gunners that can get a dead trigger, pretty much on demand, with a Benelli but they can not outrun the SLPs. The dead trigger is due to dropping the hammer before the gun is in battery. The M4 is a little faster than an M2, but the Versa-Max, which is faster than the M4, is still not as fast as the SLP/SX3/SX2.