Review of the M10 QD-L Scope Mount from American Rifle Company
Les (Jim) Fischer
July 10, 2013
Table of Contents:
1) Table of Contents
3) Background on ARC
4) Unboxing, Contents, Disassembly, and Impressions
5) Claims and Features
6) Testing of Claims
7) Summary and Conclusion (This part is short, I promise)
Preface about those rings much more interesting than the ones we buy for the ladies:
Throughout the course of researching for this review, I have come to the surprising realization that I had not spent a great deal of time thinking about what makes one ring design better than another for a precision rifle. I don’t think that this is unusual. Until a few, and I do mean very few, years ago, the sole difference between a good set of rings and a poor set was considered to be the quality of manufacture. Most rings designed for mounting on a picitinny rail had a similar design comprising of two halves, four cap screws, and a rail mount screw that interfaced with an angled piece that gripped the rail on one side and had a pivot on the opposite. Badger Ordnance rings are a high quality example of this basic design and were, at that time, often considered the “best rings”. In the last few years things have changed with regard to features, expandability, weight, and even basic design.
The first trend that I began to notice, in this break from relative stagnation, was the proliferation of quick release mounts and their increasing use on, and marketing toward, precision rifles. While long a desirable quality for AR’s because of the common use of flip down backup iron sights, quick release mounts were generally not considered solid enough for precision rifle use and furthermore did not offer any obvious advantages in this application. Nevertheless, such mounts do more easily allow for swapping optics between rifles and this is desirable to many. It is also notable with the increasing prevalence of crossover rifles between the black rifle and precision rifle classes such as the M110 and SCAR heavy, a new hybrid has come into existence that, to a great extent, displays the strengths of both classes of rifle and has some demand for quick configure ability for disparate roles suggesting different optics. I expect that the debate over quick release will continue to rage in the future, but it is undeniable at this point that many people with precision rifles are using quick release rings happily and with good results.
The trend of features in rings has exploded in the past few years as well. At this point, even knockoff rings often sport a rail for mounting God-knows-what on the top of them. Many of the major players have more refined and specific systems tailored to mounting red dots, cosine indicators, levels, and night vision systems. Additionally, as discrete rings have given way somewhat to unified mounts, cantilever and built-in MOA are also not uncommon. As it turns out, a scope mount may be used to mount a good deal more than just one scope.
The final concept, that of design and weight, is perhaps more nebulous than the other two. Weight is simple enough: aluminum, not long ago the sole province of cheap rings, is now the leading material in the best mounts available, though it is obviously not the same grade of aluminum. Regarding design though, it is not immediately obvious why one might split the rings at a 45 degree angle instead of horizontally as done in the Spuhr design. It is also not obvious why a single top cap screw and two hinges might be preferable to four cap screws on this American Rifle Company mount. These things are important though, and it is design features like these that most distinguish this latest generation of mounting systems from their predecessors.
Background on American Rifle Company and its President, Theodore Karaglas:
I met Ted this year at SHOT during the crazy walk I do the final day at SHOT through as many booths as I can get through after I have done my work visiting the optics makers and surveying their products. This walk has actually generally proven more productive than the stuff I schedule and diligently work on. I took a picture of the mount at the ARC booth, mumbled something about being an optics writer to the booth attendant, and moved on to the Cooper rifle booth in less than two minutes. I remember my initial impressions were that the machining looked excellent, the products were pricey, the booth was spartan, the single top screw was mildly interesting, All the hinges on the ARC mounts seemed unnecessarily complex, and I expected a product at this price point to have something more like maybe a level or cosine indicator mounting point.
Over at the Cooper booth, while admiring the fusion of beautiful stocks, tiny groups, and poor campaign funding decisions, the gentleman manning the ARC booth caught back up with me and said that the owner was by, wanted to talk with me, and would I mind coming back? I felt a little important, flattered, and what the hell, so I did. Ted, a Purdue engineer who worked as a machinist in college and has had a stint designing surgical devices in orthopedics and machine tools for aerospace since, was worth meeting. He was sharp, I would later find pointy, interesting, and well read. He also wanted me to review his product. Given my impression of him, the general unusualness of his designs, and my chronic shortage of mounts for review optics, I agreed. Sharp people doing strange things is worth the time invested in understanding.
Unboxing, Contents, Disassembly, and Impressions:
The mount that I requested Ted send me for review is a latest generation M10 QD-L in 30mm (rings) x 35mm (height) x 0 MOA (cant). These QD mounts run $300 whereas ARC’s M-10 rings, which are not quick disconnect, run $180 a set. The mount came in a sturdy plain white box with an ARC sticker and much larger USPS label. I have a soft spot for artless packaging, a la USO, so I rather like the simple box. Inside the box was the mount, fully assembled; a hex wrench that fits both the cap and rail clamp fasteners; and a single-sided information sheet. The instruction sheet has the torque specs on it and a few pertinent instructions, but could be enhanced by the addition of warranty and contact info. Still, it dispenses with the mandatory five pages telling me what not to shoot, clamp in the rings, or eat – and that is enough for me.
Following the unboxing, I promptly disassembled the mount, registering my impressions. The rings disassemble very easily as the pins can be pressed out with little effort when not under tension. It occurred to me that this might later allow for quarters to be made that would be able to be installed by the user and include perhaps a Dr. Optic mount. Just as my impression at SHOT indicated, the machining on this mount is excellent as well as extremely complex. Those who understand the basic workings of a CNC machine will know that a greater number of cuts, a larger number of cutting tools, more material to be removed, and the larger number of axis on which a part must be machined will drive up the cost of manufacture. This is one reason why many mounts have extraneous fasteners between parts that are never intended to be removed by the user. A more complex-to-machine single piece lower half, such as this ARC mount has, is a superior design owing to the lack of unnecessary fasteners that can loosen, will result in less stiffness, and can possibly, depending on the design, be slightly misaligned. I am not certain, owing to the huge difference between the manner in which the designs differ, but either this ARC or the Spuhr are the most machining intense designs I have encountered.
Another element that adds to the machining bill but brings great benefits is the alleviation of stress risers. A stress riser is a sharp angle in an object that can act in a similar fashion to scarring a tile to break it. These can occur at a variety of points in a mount design, but are most often found at the corners of the interface between the mount and the rail. to enhance the longevity of a mount, these sharp interior edges can be machined into little rounds. This is only done on about half the mounts in existence despite being quite advisable, especially where the material is aluminum. The ARC mount has had the pertinent stress risers carefully machined away.
Claims and Features:
Ted is an engineer and his desire was to make a set of rings, or in this case a mount, that better accomplishes the purpose of a mounting system. To whit, he has invented and patented a number of features as well as generally taking a different approach from the typical. We will here examine and also test those claims. We will first examine the claims pertaining to the unique hinged single cap screw ring design. This design claims to securely hold the scope without loosening over time while minimizing, to a greater extent than with other mounts, asymmetric pressure on the scope tube. This design also claims be easy to mount and minimize any rotation of the scope while tightening the cap screws. I should mention here that despite having a vertically split top ring, and therefore a fastener on top, the ARC mount does not obscure the shooters view of the elevation knob when in position. This is because the cap screw head has been displaced significantly to the side and the area directly above the centerline has been milled down to only .25″ above the tube. When looking above the objective bell from behind the bottom of the elevation knob is visible above the objective bell before the mount top.
The second area of the design we will mention is the rail attachment area. The quick release thumbscrew claims a tighter hold on the rail than a lever or other thumbscrew systems because the length and pivot of the rail gripping claw allows a higher percentage of the thumbscrew force to be delivered to the business end of the claw and not the pivot. This system also features a convex gripping surface in order to grip the flat, not the edge, of the rail. A PEEK (a fancy plastic used in Orthopedics) washer is present between the thumb screw and gripping claw to lubricate as well as compress slightly keeping tension on the fastener at all times to avoid working loose. The underside of the mount, where it interfaces with the top of the rail, is relief cut so that the contact points are limited to rounds near the edge in order that the rail might be sure to be gripped at more widely separated points even if it is not perfectly true. All this is claimed to add up to more secure mounting with a better return to zero. I should also note that these thumbscrews can have a hex wrench used on them so you are in no way limited to quick release functionality and may put on with the torque wrench if you so desire.
Testing of Claims:
In order to test the no-mar claim of the ARC mount, I decided to first mount a virgin scope that I had on hand. This scope was a $600 Chinese made product and that led to an interesting episode. And so, a word on cap screw torque specs. ARC rings and mounts use a single cap screw located at the top of the ring that is larger in diameter than the cap screws used in probably every other mount on the market. This means that for two reasons its torque spec is not comparable with other makers. These reasons are that you are spreading the load over fewer fasteners and that the single fastener has a larger diameter and therefore requires more torque to equate to the same tensile load. These two factors put me in the dark when it came to deciding how much torque to apply. I therefore went with the recommended 50 inch-lbs. I would not advise this. I would recommend starting at a lower value, say 30 inch-lbs, and then, if you experience the scope sliding under recoil, raising that value incrementally. This is what I, and I expect you, do when mounting a scope in conventional rings except that you probably start somewhere around 15 or 20 inch-lbs. The 50 inch-lbs that was in the instruction sheet is a likely ending value for a quality scope being subjected to recoil that is heavy but not extreme. It is not a good starting value for a low to mid priced optic, at least not mine, as it engraved that optic substantially. On the bright side, this provides for a nice segment in illustration of best scope mounting practices. The downside is the same downside you get when you over torque any scope mount that is not the weakest link. I believe the image is illustrative.
So, after the experience of putting the squeeze on the inexpensive optic, I had a big argument with Ted about recommended torque values, appropriate optic choices, and my fitness as a human being. I believe that we came to an agreement on one of these topics and I will allow the reader to make his or her own discernment as to which. I remounted the Chinese optic, and later my USO SN-3 3.2-17x ERGO, at 30 inch-lbs. Not the slightest mark was made on either from this mounting. The USO was also used in the return to zero testing at this torque on a heavy, though uncompensated, .308 and did not slide or loosen; so this torque is sufficient for this combination though a higher value would likely be necessary for a more powerful, or lighter, rifle.
In the end, it is my judgment that at proper torque, the claim of being both recoil proof and non-marring is substantiated. Also, the single screw mounting offered by the ARC was a pleasure. It was quick and absolutely no rotation of the scope during tightening of the mount was noted.
Next, let us talk a little about a mount or rings returning to zero after being dismounted and remounted. I think that the first thing to say is that there are really no such things as mounts that return to zero and those that do not. What exists are mounts offering different degrees of average change in point of aim after a mount is dismounted and remounted. The idea is to get as little average change as possible. Most companies advertising a QD product that “returns to zero” do not specify how much change is expected and tolerable and therefore amount to meaningless statements. Some, notably GDI, do (in their case, .1 MOA in lab and <.2 in field testing). That degree of repeatability would be good enough for probably any use shy of benchrest, whereas the 1 MOA claim that I have heard others informally bandy about for other makers, while it might suit the AR crowd, would not please most precision rifle users.
A number of things matter when it comes to return to zero and not all of them are the province of the rings or mount. In order to make a scope’s new location, after remounting, as close as possible to its old; it is most advisable for the designer of the mount to try to make all the variables effecting this as repeatable as possible. For instance, ARC mounts have a crowned rail interface to minimize and control the potential contact points with the rail such that a remounted scope will always have its contacts with the rail in very close to the same places. Additionally, it is also advisable that all tensions be made as similar mounting to mounting as possible. This could be achieved by applying measured torque to the rail grip screws on the ARC with a wrench. I will not be doing this as I want to know the return to zero performance of the scope in a quick release capacity and a torque wrench is not quick anything. This lack of exact tension control on the rail fasteners may be a disadvantage to the ARC vs. spring loaded lever competitors or it may be that this does not prove to be very important and that the simplicity and possible greater gripping force of a thumbscrew outweigh any disadvantage. Lastly, it is important to note that whenever you attach a set of rings to a rail, deformation of all parts will take place. This is true whenever anything is tightened anywhere but usually, in the case of the rail and mount, these deformations are small as all the parts involved are fairly stiff and the forces are comparatively small. I say usually because, if your rail is painted with say Duracote or Ceracote, or KG Gun Kote; this may not exactly be the case. On the Patriot Arms (APA) rifle that I used for testing, I noticed that the paint on the underside of the rail was squished, displaced, or missing where many rings have been attached over the years and some of this paint ended up on the ARC mount. I think that this may be quite significant to the return to zero.
In order to test the return to zero capabilities of the ARC mount, I fired four five-round groups at 100 yards with the scope removed and reattached to the rail between each group. Each time the scope was slid fully forward in the same slot and the thumbscrews were tightened as much as possible with the unaided fingers. Between group two and three, Lucas Red “n” Tacky #2 grease was applied to the threads of the thumbscrews so that the bottom two groups were lubricated and the top were not. All groups were fired from the same lot of hand-loaded ammo (.308 ammo is currently something of a problem for me as I had no stockpile of .308 bullets and I am getting to the bottom of my boxes). You will also note that the aim point for each group was the upper left of the corresponding dark block. In order to better analyze the resulting target, I used the OnTarget program. This program calculated a variety of statistics for each group. Of most interest are the horizontal and vertical offset from aim point statistics. By comparing each groups offsets to those of the other groups the displacement from the center of one group to another could be calculated and from that, the average displacement calculated.
Well, you can tell by the groups that I’m no riflery savant. I guess the secret is out. Anyhow, the first three groups have calculated centers very close to each other and, given the group size, are probably close enough to the same that not enough data exists to infer any kind of deviation of point of aim, let alone support that inference. This suggests adding lubrication had little effect. The fourth group is off a bit from the other three. All together, the average group-to-group shift in the calculated center was .355″, and this when the average displacement of a shot from the center of its group was .247″. What does this mean? I could go dig up some equations for standard deviation and try to figure out if the deviation in calculated group centers can be said to be great enough to reasonably exclude chance alone, but, given the small number of data points, I think that I would only end up finding I had a lack of data and couldn’t say much of anything with reasonable confidence. This will not keep me from speculating. People have to make decisions with insufficient information all the time. These decisions are alternately referred to as judgments when they go right and luck when they go wrong, relative to the observer. Most of the best paid people in the world are engaged almost solely in this type of decision and you can guess what my philosophical opinion on that is. Since I would like to be as well paid as, say, a Goldman Sacs analyst; I will give you my opinion and then you can risk your money and pay me a big chunk regardless of performance. I think that performance of the ARC mount returning to zero is good enough for any non-benchrest use. I also think that the unique thumbscrew driven, cantilevered, pivot rail claw is a good design. Speaking of which, I was curious as to how much gripping ability this system could possibly have when only finger tight and so for one shot I tightened the scope down after sliding it back in the cross slot instead of forward. I thought it would slide back to the front under recoil. It did not move and that greatly impressed me – more than the whole return to zero testing, in fact.
Summary and Conclusion.
Today, with regard to optics mounting products, as well as in many other areas where capitalism has been allowed to run rampant, we suffer from something of an embarrassment of riches. What once was a field comprised largely of featureless copycats that did nothing shy of holding the optic in place now contains a variety of well designed, innovative, and feature rich products catering to a variety of slightly differing needs and desires. The American Rifle Company M10 QD-L Scope Mount is one of these feature rich products and, depending on the users specific needs and budget, it may be the best choice.
The QD-L mount is a beautifully machined and cleverly designed mounting system. I find its single screw hinged ring design to be slightly preferable to the conventional four cap screw design because it exhibits no observable tilting during mounting, is remarkably quick to mount, and, most importantly, I speculate the fastener will be less likely to loosen up as it has a higher tension on it and friction is a function of force. I found ARC’s non-marring claims to be substantiated at proper torque values, though this has been the case with a variety of more conventional designs as well. I found the unique rail gripping arrangement of this optic to be functional, artful, and to have the added advantage of being either quick disconnect or not, depending on the installer’s preference. I was happy to see that in the latest generational update, ARC included a level as well as a mounting point for an angle cosine indicator. The level is, unfortunately, hard to observe from shooting position as it is centered under the optic and deeply recessed into the mount. It can be seen, sort of. Half of it is visible to the shooters off eye but the view is dark and very off center. This makes it hard to get a good read. Another change that could be made, in addition to moving the level, would be to sell additional pivoting quarter pieces with built-in Dr. Optic mounts. These would be user installed. Also of note is that the inner span between rings is 2.8″ with the length of a USO T-pal turret being 2.875.” Given that this mount is primarily targeted at high end users, I consider the exclusion of USO T-pal designs to be an oversight. This should be immediately changed as .075″ is certainly not worth excluding one of the most desirable scope makers over. It is my judgment that this mount is a good choice for users desirous of a high end precision rifle mount, particularly if they desire the capacity for quick disconnect. The price, though high, is substantially less than Spuhr, GDI, and even the Bobro dual lever designs. ARC standalone rings also cost less than Badger’s. If anything ARC is charging less than many of its closest competitors. I should note that I have enough confidence in this product that it has replaced the former mounting system on my USO ERGO and will remain there when not being used in reviews of other optics.