Monstrum Ruger 10/22 Extended Length Picatinny Rail Mount with Integrated Level Bubble

Is it a good rail? Maybe, but if you are buying it to see the level, don’t bother. The only window is on the rear, which is where it should be, however, there is no window to let the light in so the bubble is not visible without a good light source shining directly on the level.The screws are flathead, which is seldom seen of late when there are much better torx or hex head screws available.Am I going to take it off and return it? No, because the lack of visibility of the level is not apparent until the rail is mounted.Overall, it is a great idea poorly executed.

Works very good but the Bubble is too small for my old eyes and dark under the scope

This is a well-made, yet extremely affordable rail, as everyone has stated, with two and a half minor issues that I hope they fix in a revision later on down the line.First - the spirit level. As stated, the bubble and lines are almost invisible in most lighting situations. This can be resolved by carefully cutting a slot into the top of the rail to allow light to pass through. I imagine the cleanest way of doing so would be to remove the epoxy from the side, remove the vial, rout the top with a Dremel, then re-insert and re-epoxy the spirit level, however, I was able to do so with only a cheap diamond file from Harbor Freight. A straight slot makes it so that light only makes the bubble visible when held perfectly level, which could be considered a benefit, however, I wanted to see how much more light I could get to shine through, and etched out a larger half-moon shape, which allows enough light to illuminate the level even in very dim conditions. For Monstrum, I'd suggest that they rout that slot into future rails, and mask the interior when anodizing, so that incoming light reflects off the bare aluminum to illuminate the level, rather than being absorbed by the matte black finish. For anyone deciding to void their warranty and mod their rail, the metal is thin, so don't go too deep. A Dremel is probably fine, even with the level still in place, but I wouldn't suggest doing it with a drill bit, as you may hit the vial.Second - screws. Unlike others who noted issues with the length of the included screws, the length of mine were fine. However, as they are flatheads, it's easy for the screwdriver to slip off of the screw, and I could see it scratching the finish on the rail. I would prefer if they used torx machine screws like the ones included for their optics, though as it's a steel screw going into an aluminum receiver, I can understand them going with a screw less likely to strip the threads in the receiver from over-torqing.Final - Fit. The rail is fairly well-contoured to the shape of the 10/22 receiver, but there is slight gapping on the edges. It can be easily shimmed with thin tape, if needed.Final Take: I think you'd be hard-pressed to find a better rail for the 10/22 at this price. Optics mounts that wouldn't work on other rails fit this one snugly, and securely. Ultimately, the level doesn't work properly without modifications, but with care and a bit of effort, this can be fixed witout changing how well the rail works, and how well it fits the 10/22 receiver. My camera is bad and it's lit from behind, but these photos give a decent idea of how much more visible the level is with the hole added vs with the hole blocked with tape. The photo of my ugly cutting job is there to show where the vial is in relation to the screw hole and front rail lugs, to help prevent people from cutting into it. The aluminum is 0.74mm thick at its thinnest spot.

Got this for my Ruger 10/22 and it fit perfectly. It's a little longer than most picatinny rails but that's the reason I got it. The holes line up and something I noticed is that there are additional holes that you don't use for the 10/22...so this might fit on other rifles as well for flexibility.Overall, the rail mounts solidly on my rifle and works great as intended.

Its a solid product, shipped quick and fit as needed.

just the right amount of extra length for proper eye relief. solid, sturdy rail.

Fits perfectly and looks great.

This is a solid rail at a great price, they even threw in an extra mounting screw.