Yamix NFstrike 10KG Modified Steel Upgrade Spring for nerf hammershot, Sweet Revenge - Black

Certainly cannot be an actual 10KG spring, it's still able to prime with just a thumb. It might be a 7 or 8 KG, but it is not 10KG. It does however modify the blaster for an affordable price. Spring is NOT coated in shine, it has been heat-hardened through a dip in a carbon-based oil. (So it could rust.)

Put this in my Hammershot, noticably more power but its still Nerf, other physics are at play so don't expect double range or super fast darts. My best guess is its about 1/3 more powerful.

Very easy to install. A noticeable difference. Slightly harder to cock, probably not good for little kids.I'd buy again.

Super hard to pull back hammer of nerf gun when spring is installed in the gun. I would not recommend this spring unless you are an adult.

Some more power never hurts

The spring is wicked strong and makes the darts go substantially farther in my office duels with other co-workers

Noticeable performance improvement

super fun if you can handle it WARING very hard to pull back