After a number of years w/o shotguns of any kind (owned numerous Rems/Mossies in the past, even a HS Model 10 [wish I'd kept that one]), purely on a whim I purchased a Mossberg Shockwave as a b-day present to myself.
I did *not* anticipate liking it so much that I'm selling the 870 Police Magnum I purchased shortly after the Shockwave (after the Shockwave, a full-size shotgun seems "meh"). Neither recoil nor shooting it accurately are very difficult once you've got the technique down (best friend is retired LEO and can't believe I fire 00 through it).
Anywho, fast-forward to today, and after much experimentation my Shockwave now sports an XS Big Dot, GG&G modded Magpul forend (w/MagGrips panels, M-Lok rail & paraclip loop), GG&G side saddle w/QD mount, Magpul MS1 sling, an S&J follower & MFT Torch 20 lumen light* (see attached pic).
I'd experimented w/the factory corncob (had to reverse the ends of the strap for comfort), wanted a Hogue overmolded forend to work (and it does fit w/the adapter, but the bbl lug is too close to allow the action to close), tried a Tri-Star side saddle, single point sling and using the factory sling swivel studs (experimentation can get pricey, but sometimes there's no other way to find out what you need to know) to arrive at its current configuration.
I'd thought about replacing the factory safety, but since I rarely use it (cruiser ready w/safety off) I've decided not to pursue that option right now.
Using a two point sling works best for me (although some may not like the location of the paraclip loop) and hangs well. I need to practice reloading more but so far it looks like it's going to be either hold at low port while reloading w/the firing hand or similar but w/the grip pressed into my stomach (need more range time to decide).
*The only question remaining at this time involves the light. As seen in the pic below, the Torch is perfectly located to be quickly/easily activated w/the support side thumb while remaining low profile and lightweight.
Unfortunately, even mounted as far forward as possible, recoil causes the rail to painfully impact the tip of my thumb. Moving the light/rail to the 3 o'clock position eliminates that problem but makes the light slower & more difficult to activate. I tried a larger/brighter Streamlight TLR-1 there and it's easily activated both momentary & constant-on w/my forefinger, but is of course heavier & definitely not low profile (so which would you choose, the MFT Torch or TLR-1?).
Tomac
ETA: I plan on taking a local shotgun class w/the Shockwave and have put together a modular chest rig (see 2nd pic) using the AmmoPal shotgun shell dispenser (10rds of 2.75" each), we'll see how this works out.
ETA2: I found shells to be too tight in the GG&G side saddle for my taste until I applied a little plumber's synthetic silicone grease to the rubber friction bar where it contacts the shells.