I'm shortly collecting a model 500 in 410 that has a dedicated sound moderator fitted.

As the latter has no rib/bead on the front of the barrel, the plan is to fit a spare Burris Fastfire to it; I've seen another UK based shooter with a similar gun on YouTube, fitted with an Aimpoint S1 which performed very well - but I already own the FF & I don't have S1 pockets...so the FF is the ideal candidate for the job

I have done some research and believe that there is a dedicated Burris mount that is a direct fit to the 500 receivers - but it is not listed as such by Burris. Ideally I want to avoid fitting a rail or such as I want the FF as low on the receiver as possible

Anyone know which Burris FF mount fits the 500 series?
(NOT the SpeedBead mount!)

Secondly.
Where can I get spacing info on the drilled & tapped holes in the 500 receivers?
Plan B would be to have an engineer mate cobble a base/mount together

THANKS!!

https://www.egwguns.com/universal-vortex-viper-venom-670-radius-sight-mount-fits-burris-fastfire-and-docter
SKU:49325; UNIVERSAL VORTEX VIPER / VENOM .670" RADIUS SIGHT MOUNT (FITS BURRIS FASTFIRE AND DOCTER); $49.99, Availability: Out of stock but request to be notified when available. [This is the manufacturer.]

https://www.mountsplus.com/egw-universal-doctor-sight-mount-for-670-radius.html
Evolution Gun Works Universal Sight Mount For the Docter, Burris Fastfire, Vortex Venom & Viper for .670" radius; MFG#: EGW 49325
$44.99 Out of stock but can be back ordered
Mounting Hardware is Included
6-48 X .313" Overall Length
8-40 X .313" Overall Length
8-40 X .335" Overall Length
This mount has a bottom radius of .670". There should be a slight gap at the top of the radius between the receiver and the mount when mounted. The two spreads on this mount measure .500"-.505" and .8625" which should fit the receiver ring on the following guns:
Common Applications:
Shotgun:
Mossberg 500, 590, 835, 930, 935 Pre '97
Mossberg 500, 590, 835, 930, 935 Late (after '97) (Requires 8-40 and Longer Screws)

https://www.bullseyenorth.com/shop/universal-vortex-viper-venom-670in-radius-sight-mount-10356
Universal Vortex Viper/Venom .670in Radius Sight Mount (Fits Burris Fastfire And Docter) ID: 49325; $74.95 [IN STOCK!]
Bullseye North
4B - 4380 Wellington Road South
(Highway 401 & Wellington Rd)
London, Ontario, Canada N6E 2Z6
Toll Free Phone: 1-877-630-8393 -- Monday - Wednesday: 10am - 6pm EST; Thursday - Friday: 10am - 9pm EST; Saturday - Sunday: 10am - 5pm EST

May I suggest that you just skip a base plate altogether and have a gunsmith directly secure your Burris FastFire to your Mossberg 500E .410 receiver? Good luck, sir.

P.S. A red dot on a home defense shotgun is a terrible idea. A red dot sight on a sporting clays or winged fowls shotgun is a terrible idea. I think that leaves turkeys, deer, and varmints though...

Thanks for the VERY detailed answer and the links.
Will look into a few of those options!

Now, your p.s.
We cannot have home defense guns here (nor can we legally use a shotgun on deer, and there aren't any wild Turkeys in UK...)

BUT - red dot on winged things - well, I will try to link in a YouTube clip. I hope it proves to be of some interest...
It shows a Hushpower equipped Mossberg 410, fitted with an Aimpoint red dot (Micro S1 model I think) - being put to some cracking use on a field somewhere in England...

[youtube]youtu.be/SUbN5UAL6dU[/youtube]

and also from the same shooter, with some audio commentary:

[youtube]youtu.be/bQibnxmhm4w[/youtube]

Thanks.
Sometimes the links work.

Only the youtube video identifier, not the url, is used.

Fast and Furious Snow Goose Hunt Oct 6th
https://youtu.be/V6nCwJ8WXNw

No optics required by this guy.

NCStar at one point made a red dot/rail combo that fit my M500/FF3 combo. I just picked up a 590 Shockwave and would like another and they are proving to be hell to find. MSHRMDMOS is the "part number" they went by.

Edit: Zoinks, there appears to be a supply on your side of the pond!

The OP is hoping to avoid a picatinny rail or even a baseplate. Do you agree that a gunsmith can directly secure his Burris FastFire to his Mossberg 500E .410 receiver, even if it was made before 1997 when the 500 receivers began to be drilled and tapped at the factory? Thank you, sir.