NOTES FROM LUKE: The Nerf Ultra Four Spring is a custom made spring from a K26 that offers a roughly 130FPS average compared to the stock average of 100FPS. This mod is pretty difficult and you might need four hands to make it work. The geared priming mechanism makes for a really easy prime on this one as long as you get through the hardest part of getting the new spring installed.
When removing the top shell there are two little pins that have a bit of glue on them so you'll need to do a little forcing in order to pop them off. I broke one but it's not a big deal, just try to be careful there. You'll also need to use a knife or small flathead screwdriver to get the nozzle off before removing the shell. It's glued on too so you'll need to do some forcing. After the shell is off, remove the plunger tube, top gear plate, and the screw on the opposite end of the plunger.
After you have the new spring on the plunger, this is where you get to the hard part. You need to do some serious compression in order to get the lip on the plunger under the white gear train and then far enough to be able to hook the orange end piece on, then finally screwing it back into the plunger. I tried doing this alone and kept popping the internals out and ultimately had to get Luke to help me compress while I held things in and hooked the end piece on. If you do this alone successfully, let us know and we'll give you a shout out lol
-Hard difficulty on installation -One end flat, one end cut, About 128mm -Around 125FPS
SPECS: -Custom made compression spring, -Spring-Tempered Steel -Made in the USA of USA steel