My favorite assault rifle in Chapter 4, Season 3 of Fortnite... the FlapJack.
Fortnite FlapJack Review
My favorite loadout for this season has got to be the MK Assault Rifle, a Havoc Pump Shotgun, and a Flapjack for cleanup. I'll explain why in a bit.
The Flapjack rifle (introduced new for this season) is a medium to short-range assault rifle that deals an extra 40 damage per headshot compared to body shots. It doesn't have a scope and suffers from pretty wild recoil when using it at long ranges. But where the Flapjack REALLY shines is in close to mid-range combat. It has a huge magazine size and very heavy damage per bullet. It also has impressive hip-fire accuracy and in-air accuracy. Seriously, this thing is crazy good. It's the most accurate hip-fire assault rifle in Fortnite right now and has hardly any decrease in accuracy when jumping and hip-firing at close ranges.
The Flapjack has really good flexibility between close and medium range and can be used effectively as an SMG. It also has a really fast weapon swap time, so it pairs great with a heavy Havoc Pump Shotgun. I usually carry the Flapjack rifle as my cleanup weapon instead of an SMG or pistol because it's just as effective at close range and has a lot more usability at medium range, as well as a great magazine size for breaking structures and applying constant pressure.
I think this weapon pairs best with a Havoc Pump Shotgun and a long-range assault rifle like the MK, but you could also pair it with a drum shotgun to fill that medium range a little bit better. One strategy for using the Flapjack is going for headshots on unsuspecting enemies or on enemies rushing you when you're hurt. The large 40 headshot multiplier can be devastating if you land a few shots in a row, and it can turn the tide of a fight. The Mythic version of this gun can deal 264 damage with 5 shots to the head, and it can do that very consistently if you're accurate.
You can hold the gun at head level while aiming down sights, and it's very accurate when tap firing. I always recommend aiming for the chest when using this weapon at close ranges because the recoil will cause the gun to kick up to their head and capture some sweet critical damage. Now, I don't recommend using the Flapjack at longer ranges because it has severe damage falloff past 100 meters, going from 28 damage to the body at 50 meters all the way down to 18 damage to the body at 100 meters with a blue rarity gun.
The Mythic version is much more usable at longer ranges due to the higher damage and improved recoil, but it's still outclassed by every other AR at very long range. If you do use the Flapjack at longer ranges, here are the keys: this weapon has perfect first-shot accuracy when standing still and even more reduced bloom when crouched. So, while I normally never advocate being an easy target while firing, the Flapjack is best used at very long range when you're staying crouched and even better not moving at all. This is because the spread of the bloom becomes tighter when you're sitting still crouched.
The Flapjack is most consistent at long ranges when firing a medium burst of about five bullets while aiming toward the feet to allow the recoil to come to their chest. After about five bullets, let the bloom return back to normal and then repeat the medium burst again. But be very careful of getting third-partied or headshot sniped while you're standing still.
This gun is very loud and has a huge magazine, meaning it gives your enemy plenty of time to hear you and line up a shot while you're distracted firing at someone else.
Overall, I'd recommend the five-burst shot at long ranges, and at medium range, definitely go for the full auto feet-to-chest for the most consistent damage. There's a lot to master with the Flapjack, so keep practicing with it and engaging in creative deathmatches.