CHICAGO (CBS) - Nerf guns are one of the most popular toys on the market. But on Internet sites, enthusiasts are modifying their weapons to make them shoot farther and more forcefully. As CBS 2 Investigator Pam Zekman reports, they could be dangerous.
On one YouTube video, for example, a consumer shows how to make one of the battery-operated Nerfs more powerful.
"We're going to be messing with the voltage now," he says.
He switches the batteries and demonstrates how it works.
There are detailed instructions of all kinds available on various websites.
That's how 12-year-old Kenny Oostman learned how to modify his Nerfs. He showed us how he removes air restrictors, adds a spring, and hot glues metal washers with pads over them to his foam darts.
"To make it weighted so it goes farther, and the felt tip is to make it so it doesn't hurt as much," Kenny said.
With the changes, the darts fly three times farther, about 75 feet.
"He's really exploring the principles of physics, as well as being creative and inventive, and I think that that's good," said Kimm Oostman, Kenny's mother.
Many kids of all ages bring their modified toys to participate in Nerf wars. These organized events are well-regulated. Safety equipment is required, and there are restrictions on some modifications.
Modifications like the ones we found shown in various YouTube videos are not allowed at a Nerf war we attended. On those videos, you see kids shoving push pins and sewing needles inside darts so the pointed ends stick out.
"Really painful," comments one kid.
So are thumbtacks glued to the dart tips of another Nerf model that the user shoots into someone's arm.
None of those types of modifications are allowed at the Nerf war we attended that was organized by Brian Vasquiz. He knows from experience how dangerous they can be. Years ago, Vasquiz says he was knocked out by a modified dart that hit him on the side of his head.
"It was covered with hot glue and a slingshot weight inside the foam," said Vasquiz.
Users have reported "getting shot in the eye," and one said, "almost blinded."
To avoid injury, Nerf's manufacturer warns on the packaging and the toys not to modify the darts or the guns.
But users are ignoring the warning. We showed some of the YouTube videos to Nancy Cowles, Executive Director of Kids in Danger, a children product safety advocate.
"Just knowing that the possibility is out there will help parents pay more attention to the product, and to make sure that it's being used in the correct way," Cowles said.
Another incorrect use: painting any toys black so they could be mistaken for real guns, as shown by a young boy in another YouTube video.
"Even with that little, tiny orange tip," said Cowles commenting on the painted toy in the video, "the additional danger that this child is going to face is if a cop on a dark night sees him with that gun."
As for the Oostman household, none of the dangerous modifications we found -- such as adding pins, tacks or needles to the foam darts -- are allowed. But what about the modifications that are allowed?
Kimm Oostman said, "I can understand that companies for legal reasons and they're afraid of lawsuits, need to put all kinds of warnings on their products."
But she added: "I also think that Nerf would be happy to hear that there are people out there who love their toys and want to practice making them perform even better."
Not really. In a written statement, a spokesman for Hasbro, the company that makes Nerf guns, says: "Safety is of utmost concern to the company."
The company said, "Consumers should only use the foam darts designed for specific Nerf blasters and never modify the darts or the blasters."
The company also says it believes "the overwhelming majority of consumers using Nerf products do so without modifying them to suit their own specifications."
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