Discovery optical Rifle Scope Bubble Level for 1in / 30mm Tube Riflescope Anti-cant used for Shooting and Hunting

I purchased the anti cant device and it worked when I took it took it to the range. The next day the bubble had expanded to almost the full size of the glass window maybe 3-4 times the size of the proper bubble and well outside both lines. Without contacting the manufacturer and only posting a not so great review, they contacted me immediately and replaced it. I received the new device within 3 days! Excellent customer service for sure!

Photos tell the story. Discovery level vs Vortex level. Pros and cons for both. Discovery - 1. Small and dainty 2. Needs to be mounted on shooter side of turret. 3. Larger distance between bubble and side lines. 4. Bubble moves slower due to thicker fluid. 5. Bubble level glued in position. 6. About $9 Vortex - 1. Bigger and beefier 2. Best mounted on muzzle side of turret. 3. Smaller distance between bubble and side lines. 4. Bubble moves quickly due to thinner fluid. 5. Bubble level held in place by snap ring. 6. About $35. Summary: The Discovery fits and looks better on the Leupold 1" tube scope. The small size does not interfere with the turret visibility or use. The Vortex is a bit bulky and awkward looking on the 1' tube scope, but is a higher quality item. The large size mandates mounting it on the muzzle side of the turret. The Vortex, in a 30 mm size, looks and works great on a large, long-range scope, with big turrets. Final wish - That Vortex would make a quality level the size of the Discovery brand, for a 1' tube scope.

The plastic spirit level immediately fell from its mounting location. There is no sign of any adhesive or deliberate permanent or semi-permanent attachment besides "I made a hole in the thing, then I put the spirit level in the hole". The lateral edges of the "ring" (a term apparently used very loosely by the manufacturer) contact every 30mm tube I own, but only the edges make any contact. The rest pivot fore and aft from the contact points at the sides. The circumference and diameter of this monstrosity do not share the same horizon with a 30mm circle. I wouldn't accept a replacement if it came with a lapdance from a half-dozen Charlize Theron clones and a free cup of coffee. I should have known better for $12. if you want to know what it's like to buy this, set some money on fire, wait a few days, and then punch yourself in the face. It adds up the same.

Originally, I wanted to get a level that attached to the upper rail in insure that the rifle was level, then install the scope based on the level of the rifle. Those rail based levels are pretty expensive, and honestly, almost any bubble level with do. As long as you can check the level just by using your off eye (eye not looking through the scope), would be sufficient. The price was right with this level, inexpensive enough for me to take a chance, and if no, I could always use it on a cheaper build. Turns out, this little gem is pretty fantastic. Here's how I installed it: 1) I mounted my AR on a bench rest and placed a regular, smaller sized, hardware level across the rails. 2) Once the rifle was completely level, I locked it down on the mount. 3) I installed the scope, lightly tightened enough that I could spin the tube, and then placed the hardware level on the upper turret. Once the upper turret was level, I tightened down the scope, then installed the rifle/scope ring level. I have been told this could potentially be inaccurate, given that it takes three steps to attach this level, however, the installation of the scope does not change regardless of what type of level you use. I also utilized a cheap $20 bore laser in the shape of a shell casing to supplement the accuracy resolution. Obviously, there are more accurate ways to install a scope and a level, but given that most people do not own high precision tools, I think that this is an acceptable process. If I were to use a bolt action, high quality rifle, I would definitely utilize other means, but for an AR, this is acceptable.

I bought this with low expectations since it's 1/3 the price of other anti-cant bubble levels. My expectations were exceeded as soon as I opened the package and saw the build quality of the level I received. While the liquid could be a little brighter (more floressient), but bubble is very visible and doesn't easily separate. I'm still testing this unit but so far I've been satisfied.

I've purchased a few of these from different vendors and this one is definitely the best quality for the cheap price. Mainly because it utilizes a bigger level and CNC machined versus the cheaper cast ones. I've got 4 of these mounted on .22's to .308's.With that said, the biggest issue is the bubble eventually falls out so make sure you check it from time to time so you don't end up losing one like I did. Still these are great and half the cost of the Vortex bubbles. I would have given 5 stars if I hadn't lost one of the bubbles.Update 12/20/16:Received a replacement and no issues. Great customer service from these guys.

This level works well for what it is. It's not going to get your rifle perfectly level, as it's not a precision instrument, but it will keep you from canting it significantly and making it difficult to effectively adjust your turrets for longer shots. It is a bit challenging to get mounted level on your scope. The two torx nuts thread in from the bottom and if you don't alternate evenly between them while tightening the bubble will cant to one side. It's much easier to use a torx bit in a screw driver than a dedicated right angle torx wrench. The level is also smaller than I thought it would be. I have it mounted on a rather large 30mm Athlon Argos BTR. I had to mount it between the rear scope ring and adjustment knobs so it was not blocked by the scope's illumination knob or power ring. I can only see it with my left eye when behind the scope. I would've probably preferred the larger Vortex brand level, but it's nearly 3x the price of this. I also added a few drops of super glue around both ends of the bubble level to keep it in place as I've had issues in the past with similar levels losing the bubble level part under recoil.

Nicely made and not as much money as the Vortex unit.