Nerf N-Strike Elite Strongarm Main Spring Replacement - iFixit Repair Guide
Elite 2.0 Volt Mod. Pretty basic-brassed barrel, AR removal, tefloned plunger head, k26 spring, and custom catch spring. Not worth the effort. From my observations Elite 2.0 should be used as cheap
Nerf Stampede AR, Spring, and Voltage Mod | Crazy for Nerf
Worker MOD Upgrade Spring Coil for Nerf Rival Kronos Blaster | Etsy Ireland