Worker 6 kg Spring Upgrade Kit for Nerf Strongarm - Blaster-Time
Toy Gun Toys - Nerf Guns Vortex Diatron - Zombie Strike Flipfury - Strongarm and More - YouTube
Amazon.com: Nerf N Strike Elite Strongarm Toy Blaster With Rotating Barrel, Slam Fire, And 6 Official Nerf Elite Darts For Kids, Teens, And Adults(Amazon Exclusive) : Hasbro - Import: Toys & Games
Amazon.com: Nerf Zombie Strike FlipFury Blaster -- 2 Flipping 6-Dart Drums -- Fire 6 Darts, Flip, Fire 6 More -- 12 Nerf Zombie Strike Elite Darts (Amazon Exclusive) : Toys & Games
Nerf Zombie Strike FlipFury Blaster Standard Packaging - Walmart.com
Nerf zombie strike flipfury cyilnders can be used in drop barrel strongarms (instructions in comments) : r/Nerf