Too broad to answer. You have to define 'gun". A 155 mm howitzer weighs about 7 tons. A double barreled Holland & Holland .600 Nitro Express weighs about 21 lbs.
Assuming that you mean small arms it is the 30 cal Gatling gun
Heaviest gun that a person can actually carry, with normal human strength (Ok, maybe SOME steroids) is an A-134 gatling gun. The largest gun ever, period, is an M-102 Howitzer. It's a stationary gun installed in AC-130 gunships, and other very large military vehicles, fires off 102 mm shells. Enough explosive force to bring down half a block.
heaviest, heavier
Heaviest
heaviest
Heaviest tiger was 900 pouds, but the heaviest polar bear was over 2000 pounds.
No, heaviest is an adjective, the superlative form for the adjective heavy (heavier, heaviest). Example sentence:We bought the heaviest watermelon we could find.
The Airbus A 390 is the heaviest aircraft in productionThe Airbus A 390 is the heaviest aircraft in production
The fur is the heaviest in winter.
There are no perfect rhymes for the word heaviest.
Usually the engine is heaviest.
The skin is the heaviest and biggest organ