Beefed-up trigger for Nerf Rapid Fire 20 (AS-20).

Most of the stock triggers snap in half. Print this one with 3 walls and at least 25% infill. Also I recommend testing the stiffness of trigger valve. If it's really hard to press, try putting a few drops of silicone oil (or some lube that won't eat plastic or glue) down the plunger hole to free it up.