Cameron Waldrop
A tweet from Fortnite Status lists the changes as:

Striker Pump Shotgun body damage slightly reducedStriker Burst AR deals less damage at maximum rangePort-A-Forts stack size reduced from 5 to 2Two-Shot Shotgun fires its second shot faster

Fortnite dataminer @iFireMonkey has further detailed the damage nerfs to the two weapons.

Striker Pump Shotgun loses one point of damage for all raritiesStriker Burst AR drops damage by 1.75 at medium range and 2.8 at long range across all rarities

While this is definitely a huge blow to the Striker Burst AR, the recent addition of the Charge SMG seems to be more than worthy enough to be a primary arsenal weapon. If you’re wanting to test out these weapon changes before having to handle them in a real match, we have a guide on getting into bot lobbies whenever you want. This is also an easy way to complete Vibin’ quests and weekly challenges.

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Latest Fortnite Hotfix Nerfs Striker Burst AR  Buffs Two Shot Shotgun - 65