Problem with hunting between slugs and shot is that most upland bird seasons are long over by the time big game season starts so you may end up in jail/fines/guns and vehicle confiscated...Also, depending on state there is a limit to the number of shells you can have in your shotgun while game hunting--most are 5 and the Federal Migratory Bird limit is 2+1 and most states follow that for upland birds as well...
As indicated there is box magazines available for guns that keeps the centre of gravity "between the hands" where it's supposed to be and if you want more rounds then that, there is always the drum magazine(s) from IIRC 6 to 25 shells...
As indicated in the photo, a multi tube apparatus is available and from what I've read they are bloody barrel heavy and a true bitch to use...there is also a different manufacturer's model called XRail about to be released...Maybe the extra weight forward would help with muzzle climb and next shot recovery in a firefight but having to hold that "at ready" would be Hell...Try taping two 5 round boxed to the end on your barrel and holding that on target for any length of time...
I could see a viable resource for LEO/military for your product especially for the <$150 price tag...bean or rubber bullet, tear gas or pepper spray or Mace, buckshot or slug, flare or smoke or all of the above...
jaguarxk120 -- The US Military for the Dept. of Justice or Corrections experimented with a belt fed machine gun during--or just prior to--WW2 primarily for prison use--walls & guard towers, but dropped it after awhile for IIRC too slow of a cyclic rate, extremely innaccurate and of course very limited range...Looked somewhat like a Lewis Gun without the drum on top and was tripod mounted...
They also tried a Gatling Gun version and with the same results, too short range, too wide spread a pattern, can't really be aimed...Inside a building or corridor defense it would be devastating...
8 pellets per round, 150 rd per minute rate of fire = 1,200 unaimed pellets in the air per minute...M1928 Thompson sub machine gun, 700 RPM of fairly accurate fire to 100 yds, or a Lewis Gun @ 550 RPM or either Brownings M1917A1 (water cooled) 450-600 RPM or the M1919A4 (air cooled) 400-500 RPM of quite accurate fire to 2,000 yds...