Since the Mossberg 500 410 receiver is a different size than the 12ga and 20ga ones, a lot of accessories and parts for the '500' don't fit the 410 (and particularly the Shockwave).

I am interested in lights (flashlights or lasers) that work with the 410 shockwave but don't stick out too far or are too bulky.

Does anyone make a brace or blade style replacement grip?

Also are there any quick-access security solutions that work with the 410 shockwave?

Shotlock looks perfect:  https://www.shotlock.com/shop/ShotLock-Shotgun-200M-Solo-Vault-p56601416 but the ejection port stud is too big (sized for 12ga I assume?).  Has anyone tried grinding this down to fit the .410?  I am suspicious of using the trigger guard brackets (aren't the trigger guards now plastic?)

The Hornady RAPiD looks OK but I'm concerned that the .410 receiver would be too loose in it?  Also to be honest I like the mechanical quick access lock better than electrical.
https://www.amazon.com/Hornady-98180-RAPiD-Shotgun-Touch/dp/B01N4T4LSU

Smallish metal boxes (like Secure-it https://www.secureitgunstorage.com/product/hidden-gun-safe-model-47/ or V-Line https://www.gunsafes.com/Shotgun-Case.html ) seem OK but at $250-$300 are overpriced in my opinion

I am just worried that the smaller .410 receiver will be too loose and sloppy a fit and the gun could be wiggled out or fired when 'locked in'....

In.

The 410 is the only Shockwave shogun I'm interested in.

Pics of accessories for it?

"aren't the trigger guards now plastic?"

the 590A1 is the only Mossberg 500 series pump shotgun to have an Aluminum trigger guard. The rest, including every .410 model 500 variant ever made, has always come with a plastic trigger guard. They are robust and it is very uncommon for one to break (the exception may be the old style (really old) locking tabs but only if reassembled improperly into the receiver).

You going to have a hard time finding accessories for the .410 Shockwave. I have one and I enjoy for the lightweight compactness, so I am leaving it as is. IIRC- the top of the receiver drilled & tapped but I am not sure anybody offers a rail that will fit the .410 receiver profile. Maybe one for a 12 would work, I honestly don't know. If you can attach a length of rail, then you have some options. I have a Streamlight TLR-8 (combo light/laser) on my 12ga Shockwave. I really like the set-up for running around my range at night with no ambient lighting and engaging randomly placed zombie targets A very niche set-up but I have other shotguns/firearms for other purposes.

As for the trigger guards, I'd honestly rather have the plastic than aluminum. I've had beat the hell out of my 500 and never so much as knicked mine.

I didn't mean to get Mossberg fans all defensive about the plastic trigger guard.  I own multiple shotguns including mossy and other makes so I have no particular brand allegiance.  If you look at that locking device, you'll see they offer a version that has 'wedge' shapes that hold the gun in place about it's trigger guard.  I worry someone seeing the gun locked down might just try using the length of the gun as leverage and try to pry on it.  In that scenario, plastic is not what you want holding the gun into the locking device.

Thanks - yeah I have seen the SC gun locks, but the metal is shaped to fit the 12ga receivers.  The .410 receivers are much smaller and not very common so most off-the-shelf solutions wont' fit

Oh! Interesting.  I had not seen that model.  I was thinking of the in-car 12VDC locks that police and State troopers use.  But this model shown seems to need a key and I need a pushbutton/quick access version