A friend from work has a few Kifaru barrels that he bought at auction thinking they might be worth something. They are in 260 rem, 358 Win, and 300WSM. The 260 and 358 barrels have serial number 0000 stamped on barrels. The 300WSM from SN 0021. I’m wondering if these were from prototype guns, and if they could be put some use. I think he payed very very little for them.

They’re probably worth the price of a used Shilen...

I handled one of those rifles when Patrick Smith first brought the concept out. I thought and still think the concept is a goat fuck and the execution of the rifle was not impressive; think prototype not production quality. The Original Rambling Rifle was based on the Remington Model 7 using Shilen barrels and were built by Rick Steinhour. There was a second iteration of the rifle where KifaruArms was spun off as an independent entity from Kifaru Intl. and seemed to be working towards a semi-production grade but it didn't last too long.

Yes, they will be useful as tent stakes, pry bars, and the like.
For rifles; no.

Could always contact Rick, maybe he could make use of them. He's still making similar rifles, just not called "rambler". I know he's still making the stocks