Remington Model 12 22 pump

[Rafal]

We had a customer bring a Remington Model 12 pump action 22 into the shop. Serial #16173. The barrel and chamber are so pitted that a fired case cannot be removed without a cleaning rod assistance. I have searched around for info on this rifle and it lead me here. We are looking for replacement barrel We bought what we thought was the correct barrel but it doesn't match what is currently on the rifle. Some of my research leads me to believe the current barrel is not the original. I have added some pictures in the hope we can get this little thing running again. The current barrel has a different size dove tail than the replacement barrel. The current barrel has what appears to be vise marks.

Our customer wants this back in shooting condition but I'm afraid it is going to cost more than it is worth.

Thanks everyone