Another support card that protects this card from its own effect are copies of "Heavy Mech Support Platform(s)" attached to "Gatling Dragon".
Be careful when you use this, since it must destroy your own monsters if your opponent run outs of monsters on the field.
You may want to use cards like "Ojama Trio" in conjunction with this card just in case your opponent has 2 or less monsters on his/her side of the field, and your opponent might obtain a good amount of damage with this. If you do so, you might also want a "Token Thanksgiving" after the effect of "Gatling Dragon" for direct attacks.
In a Deck based on Joey Wheeler (Gambling and Red-Eyes oriented), this card has the potential for an OTK. Special Summon this card while you have "DNA Surgery" on the field, then activate "Ojama Trio" to give your opponent 3 Ojama Tokens(Preferably while your opponent controls no Monsters). Activate "Dragon's Fighting Spirit" so that this card will be able to attack a total of four times. Activate this card's effect to destroy the Ojama Tokens(Although "Lightning Vortex" may be a better choice, as "Gatling Dragon" may not destroy all of the Tokens) before attacking with this card. Keep in mind that even if you DON'T perform an OTK with the above cards, your opponent will take at least 3500 Damage.
Use the effect of "Gatling Dragon" to destroy up to 3 of your opponent's monsters, then use "De-Fusion" to get "Barrel Dragon" and "Blowback Dragon". Use their effects to possibly destroy 2 more monsters or 1 monster and 1 Spell/Trap Card on your opponent's side of the field.
Activate "De-Fusion" on "Gatling Dragon" during the Battle Phase after "Gatling Dragon" has already attacked, giving you an attack-ready "Barrel Dragon" and "Blowback Dragon" with the ability to use their destructive effects in Main Phase 2.