They don't carry the price premium they should, because they are not 'new' I suspect. They say it's like it runs on ball bearings and I think that's accurate. Search: Remington Model 10 Serial Numbers. The 31's was arguably the smoothest pumping pump gun ever built. If you do go for the 870, the police and Wingmasters versions are a better version alternatives, certainly the older ones are as good, perhaps better (according to about everyone), than the new ones. If you are thinking of getting a pump 12 ga, you won't do better than an old used Model 31. However, the Model 31 is a much better shotgun and they couldn't come close to reproducing it with today's costs for anywhere near what it would cost to make. Don’t worry because the serial numbers are not a long series of numbers that you’ll end up forgetting. This number will allow you to lookup when your Remington firearm was manufactured.

They needed to get the costs down to compete, so they did the usual things, figured out how to cut corners, eliminate hand gunsmithing and shave costs by making a cheaper version and they hit a home run with the 870. When you purchase a Remington firearm, such as a Remington 870 shotgun, it will contain a serial number or barrel number on it. Serial numbers were not a requirement until 1968, so older firearms may not have serial numbers. A serial number is printed on the receiver of each Remington rifle or shotgun, provided it’s a newer model. As an aside for people looking for amazing price to performance ratio: Remington made something called a Model 31 that predated the 870. You can also locate the serial number on the rifle’s receiver and request an age approximation by emailing Remington support.

Remington 870 serial numbers