In continuing the effort to keep my AR-15 cleaner, meaner and leaner, I've picked up a new mount for my red dot optic. I primarily run the Vortex Sparc II, paired with the occasional 3x magnifier. Vortex pairs the Sparc II with their own mount, which comes with a flat mount, a riser mount, and a spacer convert an absolute co-witness to a lower 1/3 co-witness.
I had grown discontent with the riser mount that comes with the Sparc II from Vortex as it is a solid chunky piece that weighs 2.435oz (3.095oz with the lower 1/3 riser) and uses a single hex screw as the cross bolt for picatinny or weaver rails. After a few years of swapping and remounting I've found the risers torx screw head to start stripping and retightening is more difficult. Instead of calling Vortex for a free replacement I decided to try something lighter with a better tightening mechanism overall.
The Scalarworks Low Drag Mount is a great alternative mount for the price point. Some may scoff at buying a mount thats only $50 than the Sparc II w/ mount included, but I felt the benefits would be worth while in the long run. The thumb knob was the selling factor for me, as I've never encountered anything that finger tightened so effortlessly with a rock solid clamping mechanism.
As indecisive as I am, I like to swap optics on pretty much every picatinny rail I own. Swapping between rifles, shotguns, and even pistols, the original Vortex Sparc II riser was bulky and required a tool for removal. It did provide elevation options to the user, but based on its omission from the latest gen optic the Sparc AR, its safe to say its not the slickest solution for AR-15s and Vortex has moved forward in their design department. The fact I can now move my optic forward or back on the rail, or swapping on a different firearm entirely greatly pleases me.
I sometimes choose to run a 3x magnifier behind the Sparc II, and ease of remounting to accomodate the magnifier when flipped to the side is a huge plus. If I opt to remove the magnification and position in the sweet spot just forward of the rear backup iron sight, the adjustment is quick and tool-less. Above all, the clamp the LDM uses is very strong and so far has produced repeatable zeros for my rifles, tho specific group sizes have yet to be scientifically recorded on my end.
All in all, the Scalarworks LDM is a no brainer for someone looking to upgrade their factory optic and achieve a lighter firearm. The only real negative I can point out is the co-witness height is a bit screwy when using the Sparc II. Despite having the LDM100 absolute model, my iron sights sit at the lower third position on at 15" rail. This confused me at first, causing me to return the LDM to Rainier Arms and try the lower third LDM110 model which was way too high. EDIT: Scalarworks let me know that moving forward, the LDM/Micro Absolute Model will be lowered a tad to properly cowitness with the Aimpoint T2 (and Sparc II). I'm still happy with the LDM and will continue to use it in conjunction with irons, eventhough I wish it was a perfect absolute co-witness.
FIREARMS INSIDER REVIEWS – 8 KEY POINTS
Claim to Fame: The Low Drag Mount’s precision guided telescoping clamp holds zero on every re-installation, and under the heaviest recoil. Guaranteed.
Target Market: Aimpoint/Vortex Sparc owners
FNBs (Features & Benefits of this product):
- Repeatable zero with each installation via precision telescoping clamp & thumb knob
- Lightest Quick-Detach Aimpoint Micro mount in existence
- CNC Machined from ultra high strength 7075-T6 Aluminum
- Intuitive attachment system that won’t back out under sharp recoil
- Adaptable to out of spec rails without additional adjustments
- Streamlined profile free of protruding levers or knobs.
- MATERIALS: 7075-T6 Aluminum Alloy / 4140H Steel Alloy
- FINISHES: Mil-A-8625 Type III Hard Coat Anodizing / Black Nitride™
- WEIGHT: 1.29oz LDM100 / 1.33oz LDM110
- WARRANTY: Lifetime
- HEIGHT OVER RAIL (OPTIC CENTER): 36mm (1.42″) LDM100 / 40mm (1.57″) LDM110
- COMPATIBLE OPTICS: Aimpoint Micro T-1, Aimpoint Micro T-2, Aimpoint Micro H-1, Aimpoint Micro H-2, Primary Arms Micro Dot, Vortex Sparc II
What other aesthetic options or finishes are available?: Absolute or Lower Third co-witness*
What others are saying?:
"The fit and finish on the LDM/Micro mount was also very nice. No sharp points or inconsistent anodizing at all. Just a very clean, high quality look. Another thing I noticed was that the anodizing seemed to match up color wise to my Aimpoint T-1 which at a quick glance makes it look like a one-piece Optic/Mount setup. The design itself I think is very attractive. So my initial impressions are very good. I am looking forward to using the LDM/Micro mount full time on my SBR this year. Pricing on the SCALARWORKS LDM/Micro mount is a bit higher than some of the other mounts on the market but I think the quality and lightweight/low drag aspect of it makes up for that very fast. One thing to note is that the LDM/Micro mount does not come with screws and requires that you use your “factory” screws. If you are like me and bought a T-1 with something other than the factory low mount you will probably need different screws. My T-1 came with the Factory LRP QD mount which has really long screws. Thankfully I had some screws from a different mount that I was able to use. This is not a problem, just something to keep in mind, when purchasing you might want to contact Aimpoint to purchase a new set of screws." www.AR15news.com
"I should point out that Scalarworks didn’t skimp on the clamping surface. The rail clamp runs the entire length of the side of the mount. Once the thumb wheel is turned to hand tight, the mount isn’t moving. I have the LDM110 which is the lower third co-witness model. I use it on a carbine that I purposely built to be extremely lightweight. At 1.37 ounces, it weighs less than half of the mount that it replaced on this build! To save that much weight on such a small part is amazing. The LDM seems to be extremely well made. The machine work is clean and the finish is even. The fit and finish on my example is excellent. The LDM is the lightest Aimpoint Micro QD mount on the market by a wide margin. Heck, it is lighter than most non-QD mounts. It is well made, it mounts easily, it returns to zero at least as well as is required for the precision level of the optic it mounts, and it looks pretty darn good too. This is an impressive mount and I can’t wait to see how they adapt this design to support other optics. " Jerking the Trigger Review
- Thumb Knob is knurled for grip, and employs a detent to prevent backing out
- Clamping rail is full length
- Compatible with multiple red dots
- Clamping action will accomodate out-of-spec rail widths
- Co-witnessing a Vortex Sparc II with iron sights isn't consistent with other mounts with co-witness claims: 1mm higher than other compatible optics on AR-15s, 3mm higher on a Tavor -EDIT: Moving forward this will not be an issue as the Aimpoint T2 wasn't out yet when they made the Absolute LDM Micro. The new mounts will sit lower and achieve the proper absolute co-witness.
- Included screws are button head and do not bite firmly with my used Sparc II, the original screws from Vortex are tapered head and are much more secure (may just be the internal threads on my optic are worn and the Scalarworks screws are a tad short with the head type.