I recently came across Black Aces Tactical, a Florida company making quad-rails for the Remington 870/1100 and Mossberg 500/590 shotguns.
The rail system is a single piece made from 6061-T6 aluminum alloy weighing about 16 ounces.Â The rails are black anodized (type II). The rails will accept any standard AR-type accessories: lights, lasers, coffee makers, whatever.
Black Aces Tactical states felt recoil will be reduced by about 15%.Â There is not a specific explanation on the website on why this is, but I imagine the additional weight on the top and end of the gun help reduce the recoil impulse and muzzle rise. Â An extra pound may not seem like much, but think about how much extra recoil you feel when you drop a pound from a rifle or scattergun. Â So the recoild reduction of weight is not to be underestimated.