Aimpoint and several aftermarket manufacturers offer many ways of mounting the Aimpoint to an M4. These include: carry-handle mounts and goosenecks, the military M68 mount (aka the QRP), cantilever mounts and quick-release or standard 30mm rings. I decided to use the factory QRP mount, which features a large quick-release knob on the left side and includes a ratchet mechanism to prevent overtightening. With the optional M4 spacer installed, the QRP positions the Aimpoint right in line with the rifle's iron sights. This permits "co-witnessing" - being able to use the red-dot and iron sights in conjunction or independently. Because of the glut of new mounting options that has come to market in recent years, the QRP is considered by many to be "old technology". Thus, it is often possible to find lightly used examples for sale at very reasonable prices. Although there are lighter, stronger, more versatile and more expensive mounting solutions available, the QRP will meet or exceed the needs of most civilian shooters.
I was very pleased to notice that the M2/ML2 addresses the single biggest shortcoming of the earlier Aimpoints - the fact that the dot tends to "wash out" in bright sunlight. The "CET" diode used in the M2/ML2 all but eliminates this issue, while allowing an incredible 10,000 hours of runtime on a single battery! The newer generation M3/ML3 is even better, at some 50,000 hours. My only real gripe is the high price of new Aimpoints, but this can be circumvented by buying used like I did, or opting for the slightly less rugged COMP-C2/C3 (difference being the finish and degree of water resistance).
The SPOT (Superior Precision Optical Technology) MkIII is a 30mm tube-style red-dot sight that is vaguely Aimpoint-ish in appearance and carries a retail price of around $150. It is manufactured in South Korea and imported by Mounting Solutions Plus. Each sight comes with flip-up covers, a cantilever-type rail mount, anti-fog wipes, a microfiber lens cleaning cloth, battery, hex wrench and a full-color, 14-page instruction manual (!).
The provided mount appears to be fairly well constructed, but is still far short of an Aimpoint QRP, ARMS 22M68, LaRue M68 CCO, or other top-shelf quick-release mount. It's a two-piece aluminum ring with a cantilever base that sets the sight 1 to 1-1/2" inches forward of the mount's attachment point. The top ring half is secured with 6 small hex screws, while the mount itself secures to the rail with a weaver-style jaw and a large hexagonal lock nut. Finish on the mount is a thin coat of matte black paint(?). After installing the mount on my 9mm AR, I marked the screw positions with red paint so I could tell at a glance if anything loosened over time. After about 1500 rounds, the large mounting screw backed off about 1/8 of a turn - enough to create some play - but stayed attached to the gun. I re-tightened and re-marked it, but will probably replace the factory mount with an Aimpoint QRP or other high-quality mount.
The flip covers provided with the SPOT are a quasi-hard rubber (softer than Butler Creek/Aimpoint) that open and close quite securely. The brightness adjustment is a large wheel on the left side of the scope body, featuring a large threaded cap under which resides the flat CR2032 battery. There are 11 brightness settings and an "off" position. Each increment is a positive detent on the knob, and the knob can be turned either way (i.e., you can go from "0" straight to 11 without going through 1-10). Battery life is listed at 150 hours "before the dot intensity begins to fade considerably". Twice, I have accidentally left the SPOT turned on at low brightness settings for days at a time, with no degradation in brightness. I would say the 150-hour figure is either conservative, or assumes the brightest setting.
Windage and elevation adjustments are click-type dials located on the top and right sides of the scope. Their covers are secured by a rubber strap that attaches to the scope body behind the rear flip cap. The brightness switch, battery compartment and W/E dials are all O-ring sealed. The sight is advertised as "water resistant".
Finally, the SPOT's 4MOA dot is among the brightest I've ever seen, and it is nice and spherical with less starbursting than in many of the less expensive types. There is a noticeable bluish cast when looking through the sight, which I am told has to do with the coatings used on the lens. The OKOs show this, too, as do the Aimpoint ML2s to a lesser degree. As expected, the SPOT passed the washout test with flying colors.
I am quite happy with the quality of the SPOT MkIII, especially in light of its relatively low price tag. It puts other sights in its price range (primarily the Hakko Tacpoint) to shame in terms of quality, and meets the needs of most recreational shooters for about half the price of an Aimpoint COMP-C2.
ARMS #40/40L BACKUP IRON SIGHT
The ARMS #40 was designed to serve as a backup iron sight (BUIS) for use if rifle-mounted optics should fail. It folds flat and locks down using a retainer bar, allowing it to fit under large scopes or remain stowed when not in use. Because the sight is under spring tension when stowed, flicking the retaining bar out of the way causes the #40 to be instantly deployed to the "up" position. This same spring tension keeps the sight upright in the event it is bumped or the rifle is dropped. Because of this, the #40 may also be left in the deployed position and used as a semi-permanent rear sight, either with the standard front sight alone or in conjunction with red-dot optics. The latter is my chosen method of employment.
The #40's L-shaped sight leaf contains both a large "ghost ring" aperture for use out to 300 meters, as well as a small long-range aperture. The latter incorporates a built-in horizon line and notch to help lead distant targets and to help prevent the rifle from being inadvertently tilted during long-range precision shooting. Its windage adjustment knob (there is no elevation adjustment) is a low-profile affair designed not to interfere with operation of the charging handle with the sight in the stowed position. The #40L is generally similar, but features a reduced-size adjustment knob and slimmed-down flip-up housing with two-piece sight leaf. It is designed for applications where space is limited, such as under low-slung optics. My only gripe about the #40L is that because of its design, it must deploy with the small aperture in position (as opposed to the large aperture, like the #40). This is less than ideal for the close/fast shots for which an emergency or back-up iron sight would most frequently be used. The only real way to fix this issue is to disassemble the sight and remove the small aperture leaf entirely.
Simply put, the ARMS #40 and #40L are bulletproof. They are compact, rugged and very well-engineered - as it should be, considering it was developed for and is in use with US Special Operations forces. This also means that it is expensive for the average civilian to purchase, and may at times be in short supply due to military contract obligations.
VLTOR ADJUSTABLE CARBINE STOCK
The VLTOR (pronounced "UL-TOR") Modstock is an adjustable AR-15 stock of advanced design. Modstocks are available in standard or "clubfoot" profiles and in several colors. The most notable feature of the Modstock is the interchangeable side pieces – either a "cheek weld adapter" or a hollow accessory tube. The "teeth" on the side piece interlock with the those on the cheek area of the stock, and a single screw secures the side piece to the stock body. Both side pieces offer a more comfortable cheek weld compared to the standard M4 style stock; the cheek weld adapters are lower-profile, while the accessory tubes allow watertight storage of batteries or small parts. The accessory tubes are sealed at the back, and the front openings are covered by locking caps.
The VLTOR Modstock will only fit mil-spec receiver extensions (buffer tubes) such as Colt, LMT and CMT/Stag. VLTOR also manufactures its own tube for use with the Modstock. Fit of the stock body to my CMT receiver extension was tight enough to eliminate rattle and provide good stability, but not so tight as to make extending and retracting the stock difficult.
My only real gripe with the Modstock is that the "long" accessory tubes furnished with the stock can complicate the installation of certain types of slings, since some rear sling adapters may not be long enough to encircle the stock with the tubes attached. One can alleviate this issue by swapping the long tubes out for the older "short" versions which do not interfere with the slot in the stock body, by attaching an Uncle Mike's QD sling swivel to the built-in mounting point instead of using a nylon rear adapter, or by using a rear sling plate instead of attaching the sling to the stock. Another minor concern is the accessory tube caps; the fit is tight enough and the latches are small enough that removing the caps under stress or with gloves on is very difficult. Additionally, the caps should be "dummy corded" to the stock itself to prevent them from being lost in the field.
I am pleased with the quality and overall feel of the VLTOR Modstock. I believe it represents an evolutionary, if not revolutionary, improvement over the standard M4 and CAR-style stocks, and is a better value than some of the other high-end stocks on the market. That said, are storage capacity and a more comfortable cheek weld enough to justify the Modstock's high price (about double that of an RRA M4 stock)? That's going to be up to the individual user to decide. Personally, the storage capacity is not a huge selling point; I also have space for batteries and small parts in the aftermarket pistol grips and vertical grips found on all my ARs. I do, however, like the improved cheek weld provided by the VLTOR, and this was sufficient justification for putting one on my M4, Recon Carbine, and "Practical" AK-74. For non-critical applications (i.e. "fun guns"), if you are looking to equip a large number of rifles, and/or if money is an issue, you'll probably better off sticking with the standard M4 stock.
VIKING TACTICS VTAC SLING
Mag-Cinch is a product from Buffer Technologies that attaches two magazines together on the rifle, allowing the spare mag to be kept handy for a quick reload. Essentially this product provides a simple, functional alternative to the duct tape and stamped-metal "jungle clips" that soldiers have used for years in an attempt to accomplish the same thing. Each Mag-Cinch consists of a polymer T-plate and back plate connected by a long screw and equipped with an adjustable nylon strap. The plates are used to properly position the magazines, then the screw is tightened to provide the inital pressure. Finally, the ends of the strap are cinched down to secure the magazines in place. For maximum security and rigidity, two Mag-Cinch units are used for each pair of magazines.
I have used the Mag-Cinch extensively on my M4 in tactical rifle competitions. With a cinched pair of 30-round magazines in place and another mag in a Tactical Tailor stock pouch, I have 90 rounds available on the gun, which is by far the best place to keep spare ammo for quick reloads. The initial reload with the cinched mags is very fast - simply release the pair, slide it over to the second mag and re-insert!
Initial setup of the Mag-Cinch takes a bit of trial and error; both both mags must be able to lock in completely, and the "extra" mag cannot block any weapon controls or the ejection port. Once the proper positioning is found and the Mag-Cinches are tightened down, the two magazines become one solid unit and will not shift under rough handling.
RRA 2-STAGE MATCH TRIGGER
This aftermarket trigger kit from Rock River Arms greatly improves the trigger pull on AR-style rifles. The RRA match trigger installs just like a mil-spec trigger group, and can be done by any operator with a working knowledge of his rifle's internal mechanisms. I have not measured the pull weight on the RRA trigger, but I believe it is DCM-legal which is around 4 lbs., though its smoothness makes it feel much lighter. The pull is a two-stage type, with a light, smooth takeup and just a bit of stacking leading up to a crisp break. There is no overtravel, and the trigger can be let out just to the point of reset for a fast second shot. Because of its simple, nonadjustable design, the RRA unit is among only a handful of "match" triggers suitable for use on a duty or defensive rifle, and is the ONLY such trigger in its price range! I have them in all my .223 AR's.
The RRA match trigger seems to need some breaking in before optimum smoothness and function is achieved. After I first installed it, the trigger was noticeably gritty and failed to reset a few times. After putting a few hundred rounds downrange with the new trigger, the grit had vanished completely and the failures had largely abated as well.
FOBUS G27 PISTOL GRIP
The G27 from Fobus/First Samco is the newest contender in the crowded field of aftermarket pistol grips for AR-style rifles. For my money, however, it's also the best of the breed. Constructed from semi-hard plastic, the G27 combines key features from other AR grip designs, including: ambidextrous design with molded finger grooves; an arched, palm-filling backstrap for a better grip and more ergonomic trigger finger placement; a built-up grip tang, non-slip surface texturing and a sealed interior storage cavity. The G27 is both solid and very comfortable, and its design automatically orients the hand into a "correct" firing grip. The storage cavity is capped by a removable rubber plug in the bottom of the grip. Turning the coin-slotted plastic locking plate in the center causes the plug to expand, thus sealing the cavity. The Fobus G27 grip is somewhat expensive at $24.95 MSRP (compare to a $16.95 Hogue or a $12.00 Lone Star trapdoor), but is about on par with the Ergo line and other aftermarket "tactical" grips. The rubber plug can be difficult to remove when accessing the storage cavity (a thin screwdriver blade or other flat object can be used to pry the end up), and it does not afford a watertight seal. Even with these minor complaints, the G27 is an outstanding enhancement to any AR-type rifle.
MIDWEST INDUSTRIES MCTAR-20 RAIL SYSTEM
The MCTAR-20 from Midwest Industries is a carbine-length free-float rail system that consists of 4 pieces - the upper rail assembly, bottom collar, front cap and bottom rail. The upper rail and bottom collar clamp around the standard barrel nut (delta ring must be removed) and screw together, indexing on the barrel nut teeth for proper positioning relative to the upper receiver. The front cap is then attached to the inside of the upper rail, and the bottom rail attaches to the front cap and bottom collar, holding everything together.
The MCTAR-20 is well machined and nicely finished. The rails themselves are dimensioned to mil-specs, feature laser-marked address numbers, and will accept all rail-mounted accessories. Installation is pretty straightforward; the required allen wrenches and thread-locking compound are included. The only hitch I ran into was installing the front cap; the screws have to be inserted at just the right angle, and since you're putting steel screws into a threaded piece of aluminum, it would be very easy to cross-thread them. I had to start the screw on one side just enough to hold the cap, then start the other screw. Go slowly, and if you feel an unusual amount of resistance, back the screw out and try again to get the right angle. Once I finally got the cap installed into the upper rail, the lower rail attached with no problem.
At 11 oz., the MCTAR-20 is only slightly heavier than the YHM lightweight (10.6 oz) tube I previously had on my 9mm AR, and a bit lighter than the Samson MRF-C (13 oz.) that I have on my M4. Installed, the MCTAR-20 is rock-solid, but it does not install as easily nor is it as robust as the Samson, which features four massive locking screws with built-in helicoils on the collar and a dual-retention system (spring-loaded detent plus locking screw) for the lower rail. The MCTAR-20 is, however, almost half the price of the Samson, and as such, offers excellent construction and performance for the money.
MAGPUL MIAD MODULAR PISTOL GRIP
The MIAD (MIssion ADaptable) grip from Magpul Industries is a drop-in replacement for the A1/A2 style pistol grip that features interchangeable frontstraps, backstraps and inner cores, which allow the grip to be customized for individual hand sizes, preferences and mission requirements. The MIAD Basic Kit comes with the chassis, 3 backstraps (flat, medium beavertail and large beavertail), 2 frontstraps (straight and finger groove), and a core insert that holds 3 rounds of 5.56 ammunition. The Full Kit also includes an additional finger groove frontstrap, and one with an integral oversized trigger guard. Other core inserts are available separately.
Installing the MIAD on my Recon Carbine using the supplied instructions was straightforward, though the chassis may require some light filing or "persuasion" with a rubber mallet in order to fully seat on some rifles. I experimented with all of the different front- and backstrap combinations prior to installing the grip on the gun, then changed the configuration a couple more times afterward, before finally settling on the medium beavertail backstrap and finger groove frontstrap. The fit of the chassis to the receiver and of the components to the chassis is extremely tight and solid, and the surface texturing provides additional purchase without being uncomfortable.
My only real gripes about the MIAD have to do with how it is marketed and sold. It is only available in kit form, so once you buy the first kit and establish what configuration works best for your needs, you have a bunch of parts left over. And when you go to buy the next one, you are forced to essentially pay extra for components you will never use. Additionally, the 3-round core insert included with the kits is virtually useless in all but an extreme survival situation; I simply use mine as a plug, since I keep batteries and small parts wrapped up in a baggie inside the pistol grip's storage cavity. I would like to see Magpul or some enterprising dealers offer an "ala carte" approach, wherein the chassis and individual components are available separately, so users can piece together the exact configuration they want. While a lower price point for such a setup would be nice, I would pay the kit price for it, just to eliminate all those extra parts that will go right into my junk drawer.