Good Riser/Perfect Height
I bought 2 of these mounts to install a Red Dot scope on my AR build. You will have to take the screws out completely and move the charging handle back out of the way and slide them on the rail from the rear. These are not traditional 2-piece mounts, they are solid 1-piece construction. I initially snugged them down carefully with the included T-15 Star ended Allen wrench. They would not tighten without some wobble left in them, hence my call to Burris. The Rep. told me that the recommended torque is 45/in.Lbs. but that is generally not enough to snug them down. He told me in their testing that generally over 100/in.Lbs. of torque was needed to tighten sufficiently. He recommended NOT using the included Allen wrench and use a T-15 Star bit screwdriver. I completed the installation and they tightened down quite well. Solid as a rock now. No stripping of the screws. He also told me that if they broke they would replace them no questions asked. The sight height is now perfect for Co-Witnessing through my Red Dot with my Magpul rear flip up sight to the standard A2 front sight.
How to get the Riser tight
Poor mounting design. Cross bolts should be beefy hex head. Impossible to get tight without stripping bolt heads. However was able to use bench vise to squeeze mounts so that the cross bolts could tighten the mount for a tight fit. Be careful not to squeeze the mount too much and have to pry the mount open to fit on rail. Good concept but poor design.
Trash
The mount is not true Picatinny, the footprint is larger and it will not tighten on the receiver rail. I torqued to the screws to the recommended 20 foot pounds and it is loose and moves forward and backwards. The screws cannot be tightened further without stripping, so this riser is essentially useless trash. as soon as I opened the packaging and saw the “Made in China” sticker on the bottom I knew this wasn’t going to be a good accessory. Disappointed because Burris claims to be a Colorado company. At least I now know not to buy anything else from them in the future.
Not So Great Riser
It does fit to a Picatinny rail dovetail but the clamping screws do not fit the spacing groves on a Picatinny rail. Therefore I could not recommend this product for a Picatinny rail mount project. Also problematic is that this product does not have separate side clamping piece to attach to the rail. This could make your mounting project much more difficult.
unusable junk
without a movable clamp to the pic rail, the entire riser must clamp itself to the rail. however, it is an alum casting without any ability to "spring" at all and it is at least .050" oversize to begin with. After tightening the hardware you can grab the riser with your fingers and rattle it back and forth. (side to side)
Do not buy
The rail cut is way oversized, requiring a tremendous amount of tightening before it becomes snug. My guess is that most people break screw driver bits try to secure this thing. I do not have any faith that this product will securely hold any optic. Once it was finally tightened a stress line was visible right down the middle of the mount. Will never use this again and urge others to try another product instead.
Poorly designed - returned for refund
This is a solid one-piece riser that relies on flexure across its top to lock the riser to the rail when the mounting screws are tightened. It is badly designed and works very poorly. I purchased two and was unable to tighten the screws sufficiently on either of them to lock the riser to the Picatinny rail on my rifle. I am returning them, and strongly recommend against anyone purchasing this item.
Chinese made garbage. Do not buy
Diameter of cross screws is much to small to fasten the riser to a Picatinny rail properly. Think Magpul MBUS, and how the cross screw fills in the rail slot to prevent movement. When installed the rail has a lot of front to rear shake and would likely never hold a zero. Attempts to torque the screws hard enough to deform the riser enough clamp to the front sight will only result in stripped screw heads and a stripped wrench. The material used to make the screws is much too soft. Product is unsurprisingly made in China. This product is garbage. do not purchase. Would give zero starts if I could.