Monstrum Red Dot Mount Compatible with Mossberg 500/535/590/835/Shockwave Series Shotguns

I have a vortex viper and the fit was perfect. The kit comes with several different screw sizes to fit different shotguns. I have a Mossberg 835 and the screws worked perfect. The dot mounted to the adapter with no issues. Good product

This is as low profile as it can be, fit great and came with all the necessary screws to be up and running immediately. Purchased the Mossberg 500/590 version and it was perfect for the shockwave. As long as you choose the correct model for your shotgun and optic, this is what you're looking for.

Very low profile . Works great with the original stock. No need for a riser

Much better mount than picatinny rail.More in line with the sight line.2nd mount I bought for my red dot.Easy to install and comes with a variety of mounting screws.

only came with 2 screws to mount plate on to gun and they go too deep in the receiver for the bolt to cycle, avoid if you have the 940

First off the mount itself is finished well IMO although like others stated it could have been designed a little differently to reverse it if desired which would solve my particular issues. My 590 is a 1993 (confirmed by Mossberg) with factory installed 8-40 receiver "dummy screws" although they only drilled for three of them and apparently about 1/4" more rearward than most. That puts this mount's rearmost screw boss on the slope of the receiver resulting in a tilt. No idea why my gun was drilled like this and neither did Mossberg when I asked.After drilling and tapping a 4th forwardmost hole the mount fits but there's that taper to deal with at the rear. The Venom sits in the center of the plate but the pins aren't centered, the RDS will reverse on the plate, so the mount reversed solves the tilt issue and brings the optic back a bit (preferred), but will require new RDS mounting holes drilled, and the plate is shaped to fit the Venom so with it reversed it looks a little goofy. Option #1.Option #2, either shim the rearmost screw boss, or cut it off and run the mount with 2 screws only. Not preferred but would work.As others noted the provided screws are junk. The provided "Venom" screws are too small diameter to properly fit the RDS, pic shown. The mount to receiver screws are supposed to be 8-40 but are sloppy fit, sloppy hex, and too few threads exposed when placed into mount. I sourced Hillman 8-40 x 1/4" optic ring screws from local farm supply, MUCH better solution.Cosmetically as others noted it is bulky, I'll taper the ends a bit with a grinding tool probably and smooth the appearance.A lot more than some would deal with I'm sure but I like fine tuning stuff. But those supplied screws need to go. And to answer my own unanswered question from here and Monstrum, the plate is 2.07" in case somebody wants a longer Docter pattern RDS.

There are a lot of products that "you get what you pay for" in the 2A industry but this isn't one. It's a very simple product; a piece of metal with minor machining and a couple of holes drilled through it. That shouldn't be expensive yet so many are. Great product at a good price!I'm using it for a Mossberg 835 with a Holosun 507C and it works perfectly

Great product