& I must ask ....
What "advantage" would a SST shotgun entail?
May be a "nifty," & a "must have," & "a better" finish, all-in-all, but when it really comes down to a "nuts 'n bolts" pump/"do-it-all" shotgun, what possible difference could it ever matter?
You could literally soak an 870 in salt-water & just flush it out "one-a-week" with fresh water & still have a perfectly functunal pump-gun.
Why a "better" finish?
I literally did have a Rem Express which, when dove hunting in NW Nebraska once, exposed this thing to an an extreme amount of sand ..... (it was literally buried & my buds were absolutely horrified) when I just ran "the pump" over the shotgun to flush all the sand off it. The "pump" was merely "the house" water-hose-thing .... this is a country watre pump, BTW ... not some "purified "city-thing."
Yup. Turned the pump on full, ran water all over the shotgun & worked the action forcefully enough to work out all extraneous material/s - "blew" the sand out enough to re-work the action. Fine enough to shoot ~75-90% on doves till I got it home.
When I got home - a week, or two, later, I did spray on some CLP & "cleaned out" the action & etc.
- YMMV.
There's not another that'll take this kind of "abuse," stadard-level of "attention" & keep on keepi'n on .....
Another BTW - zip for rust on this shooter & it's still one of my #1 mainstays for home defense & for every reason to be so = total reliability & (still) zip for any rust/corrosion, etc. - this & 4+ years later.
Stainless/nickle-plate = why the extra expense?