Even shotguns are not immune to the basic law of firearms:
EVERY gun/barrel/ammo brand & type combination is a law unto itself.
Case in point: Shooting Budd & I both have Maverick 88 shotguns with the 18-1/2" cylinder bore barrel. Mine throws the best patterns with Rem #4 Buck, while his works best with Win #1 Buck. Another Budd with a Mossberg 500 and the short barrel finds his is best w/Fed 00Buck.
"Slugs?" you say? Again, Your Mileage Will Vary. Mine best with PMC brand 2-3/4" 1-Oz, worthless with Rem "Sluggers". First Budd's is best with Sluggers, while 2md guys guns like the Brennekke KO slugs.
Load your weapons and 'Stand Ready'. It will be a bumpy ride.