[F*W*F]

I have a BPS Trap, a Model 12, a Stevens 620, three High Standards, a couple 31's, and around a dozen 870's (including 5 TC's and 2 TB's). My only experience with a Mossberg was my brother's New Haven 600 (a department store 500). I haven't any experience with a 37, but I'd like to get one sometime.

"Best" can be defined in different ways.

If machined steel innards are your thing, the earliest designs on the list will tickle your fancy (12, 31, 37 {which is actually a 17}, and the Browning designed Stevens.

If you add smoothness to your criteria, the tipping breech bolt designs will rise to the top (31, 12, 37). The High Standard is also in the tipping bolt group and just as smooth, but the overall workmanship isn't quite on the same level.

After WW2, cost cutting/efficiency comes more into play on pump guns, and I think of the High Standard as a simplified and Fieldmastered Model 31. The 870 replaced the 31 (which Remington claimed lost them money every time they sold one). Much of the machining in a 31 was simplified in the 870, or replaced outright via stamping. And the ultra smooth tipping breech bolt was eschewed for a tipping locking bolt which could headspace into an extension on the barrel, facilitating quickly interchangeable barrels. The next step down the cost cutting path is the Mossberg, which I think of as an 870'd High Standard. The 500 takes full advantage of the bolt locking directly to the barrel extension, and makes the receiver cheaper to machine by switching it to aluminum. The 500 is simply cheaper to make than an 870, and Remington's mistake with the Express was to price match the Mossberg.

I don't know if Remington even contemplated an aluminum 870. The aluminum 31L was problematic, and aluminum just cannot look exactly like blued steel. Furthermore, they wanted some cross platform production efficiency, not only between the pump and autoloading shotguns but also with the rifles, and steel is the easy choice to cover all of them. And if you see an 870 cut through, there's not a lot of material there to save weight on with aluminum.

The BPS has plenty of exterior elegance, but unlike the older bottom ejectors with their tipping breech bolts, it has the tipping locking bolt engaging the barrel extension, so it shucks more like an 870. Reassembly can also be tricky, enough so that Browning counsels owners not to remove the trigger assembly.

My favorites? The 31 is at least as slick as the best of the pre WW2 designs, it has the righty friendly ejection/singles loading port of the Model 12, and I believe it feels like it has a bit more of its weight centered between the hands than the 12. It just feels elegant while you're running it.

Overall, though, the modernized 870 still manages to look good, especially in the nicer Wingmaster and target grades. Speaking of which, it's the last pump which was designed to handle a serious competition schedule; look up what all Rudy Etchen did with his. Most repairs are pretty easy; ejector replacement does require riveting, but the staked in shell latches aren't too tricky to replace. Parts are plentiful on eBay. If you're worried about a breakdown while at a trapshoot, a spare bolt assembly and trigger group will get you out of most foreseeable jams in a matter of minutes. And maybe it's not as smooth as the earlier designs, but its dual action bars certainly make it more bomb proof.