11mm Dovetail to 20mm Picatinny/Weaver Low Pro Snap-in Rail Adaptor 4 Slot & 9 Slot for Red Dot Reflex Holographic Sight Laser Scope and Other Optics

This piece is perfect exactly what I was looking for I don't know why there is so many negative reviews you just got to use your common sense and it will fit perfect FYI put some Loctite on the small screws and oil the pins and squeeze it together a couple of times and you're good to go

Does not work. It’s dove tail is way to small to grip onto most receivers. For me to use it on my rifle I would have to file or mill down the top round of my receiver.

11mm Dovetail to 20mm Picatinny/Weaver Low Pro Snap-in Rail Adaptor 4 Slot & 9 Slot for Red Dot Reflex Holographic Sight Laser Scope and Other Optics .I used this to add a red dot sight to a crossbow pistol that had an 11mm rail, but my micro red dot fit a 20mm picatinny rail. This worked perfectly. The red dot clamping on the picatinny rail also clamps the adapter to the 11mm dovetail rail. I am happy with this solution..

Nice low profile adapter. This let me mount a spare red dot to my old Nylon 66. Super simple, just pop the adapter section into the picatinny jaws on the optic and install like normal onto the dovetail. The optics rail screw clamps the adapter onto the dovetail and everything mounts up solid. Not sure this would work with a QD optic mount, but for a bolt-on it's solid.

I opened the product and started installing it and the set screws instantly stripped all the threads making it useless.

The concept of this adapter is great, the material quality is great, but the design is a fail because of one crucial flaw. Although there are horizontal end set screws to hold the adapter in the closed position, they do not any clamping pressure to keep this adapter rail solidly mounted, and it slides forward and backward with a scope mounted. There is too much smooth contact area inside the adapter rail's edges. It must be modified with a vertical set screw to act as a rail stop to prevent that undesired movement. The manufacturer should recall all of these and modify them with a vertical set screw, or else trash them which would be a shame because they are otherwise well built. Of course, you can modify it yourself if you have a drill and tap set and a spare set screw to match the thread size. That would be less than an hour's work for most people. Or else, buy the smaller 1 inch size of these adapters which are properly designed with a vertical set screw. The 1 inch size is sold in as set of two, so you can just use two in series if you want to have a longer length picatinny rail adapter.

Bought to add standard rail to top of Rossi .22 pump. Those have 3/8 groove.Gave me the rail to mount a Fastfire 3 to the synthetic stocked galley gun.The biggest bonus is the very low profile this added. Most 3/8 to Pic rail adapters add 1/2 to 1 inch to mounting height. This only added about 1/4 inch. Fits close enough and small enough to not protrude. Just slightly longer than the mount on a FF3. Fits tight enough that less likely to snag.

I used the four slot model to mount a Vortex Red Dot with a picatinny rail to the 11 mm dovetail slot on a Sig Trailside. You just pop the adaptor into the base of the optic and install it on the slot as a single unit. Tighten up the set screws in the ends of the adaptor, then use the optic's hardware to hold the assembly in place.I appreciate the fact that this does not change the mounting height of the optic. I have run about 500 rounds through the setup and it didn't move at all. That was a large concern of mine. No problem. There isn't much recoil from a .22.So far so good. In order to clean the Sig it is necessary to remove the optic for field stripping. That is just the nature of this particular piece. (it would be that way with anything mounted on the barrel rail) I will see how it holds up after repeated removals.