By MikeG
April 19th, 2009
Features & Design
The Aimpoint CompM4 red dot sight is the first significant update to Aimpoint’s classic CompM2 & M3 sights. It was designed to be more streamlined and convenient than its predecessors. Updated features include an integrated mounting system (similar to the Quick Detach Mount sold by Aimpoint for the CompM2/M3, separately, for about $100), enlarged dimmer, battery cap, and mounting knobs, and it runs on a single standard AA battery (its predecessors used proprietary lithium batteries).
The adjustment & battery compartment caps are all still tethered to the sight by rubber retainers, though now each retainer is separate, unlike the single large retainer that held all the caps together on the CompM2/M3. Aimpoint has dispensed with the rubber ‘raincoat’ introduced with the CompM3 that was intended to protect the sight from bumps and scratches. Also no longer included are flip-up front and rear lens caps and instead includes a rubber ‘bikini’ style lens cover. However, original Aimpoint lens caps can be fitted to the CompM4, as it has the same front a rear lens sizes and retention grooves.
So why have I spent so much time talking about the real CompM4 that retails for around $700? Because this replica is Incredibly similar to it. The replica sports all the same features and even includes accurate trademarks.
Look & Feel
I purchased this replica at a 50% discount for $28.24 from RSOV.com during an inventory reduction sale. The sight normally sells for $56.49. It came packaged in a unmarked cardboard box. Inside the box, the sight was well protected – surrounded by thick foam on all sides. Included in the box were: the sight itself, rail mount, rail mount spacer, two sets of screws, a 3mm hex wrench, and a small yellow lens cleaning cloth.
The sight is just as solid feeling as a real Aimpoint and has a nice matte black anodized finish. It appears to be a Type-I hard anodized finish (as opposed to a Type-II finish which is more durable) based on how easy it is to scratch. That’s not to say that it IS easy, just that this features the more common and cheaper finish of the two.
All the knobs and caps look well made with sharp checkering and grooves. Unfortunately, they’re made of very light aluminum and screwing them on or off results in a feeling much like sandpaper.
As I mentioned before, this replica has excellent trademarks.
The primary trademark reads:
CompM4 1370993
Made in Sweden
There are two other faint “Aimpoint” trademarks etched into the left side of the body of the sight and into the right side of the battery tube. They have the right typeface and look nice when you actually catch a glimpse of them.
When I bought the CompM4, I also ordered the replica KillFlash that RSOV has on their website for $4.99. The KillFlash is a device that helps to eliminate the bright reflection from the red lens on the front of the sight. It is a small hexagonal grating that screws into the front of the sight and only allows light to pass through within about +/- 10 degrees off the axis of the sight. For someone looking though the sight, it should be mostly invisible. This replica KillFlash does what it is intended to do; when viewed off-axis, the front lens is no longer visible.
Unfortunately, the replica is not perfectly hexagonal throughout and the material it is made from is slightly thicker than that of a real KillFlash. This makes it slightly harder to see through while aiming, but the price, effectiveness and aesthetic it adds are still WELL worth it.
To protect the lenses of the CompM4 replica, you are supplied a rubber ‘bikini’ lens cover, just like the real CompM4. This is a pair of rubber caps linked by two rubber straps, while I do like this cover for it’s protective value while storing the sight, I cannot see using it in the field. It is slower and less convenient than the spring loaded lens covers on previous Aimpoints, and unlike them it is not linked to the sight, so it is possible that it could fall off if not carefully used.
Operation & Performance
The oversized dimmer knob on the CompM4 makes it even easier to operate than previous models. It has 10 positions: off + 9 brightness levels. The levels are well distributed, from ‘barely on’ to ‘visible on a sunny day’. The knob clicks into position firmly, unfortunately, the dot will sometimes go off while in one of the on positions. A little wiggling of the dimmer knob will usually bring the dot back, but it is annoying nonetheless. I suspect that the switch that the knob operates does not always make good contact.
As stated earlier, this sight is powered by a single AA battery. This is a huge advantage over the tiny, specialized, and usually low capacity watch and button cells used in most airsoft red-dot scopes. The AA allows for an incredibly long battery life; I would predict at least 3 days of constant ‘on’ before it runs out. To be honest though, I haven’t changed the battery or noticed a decrease in brightness since I received the sight, even after leaving the sight on for about 30 hours.
ACM CompM4 Dot on Shadowed Surface – Max Brightness
Aimpoint CompML3 Dot on Shadowed Surface – Maximum Brightness
ACM CompM4 Dot on Sunny Surface – Maximum Brightness
Aimpoint CompML3 Dot on Bright Surface – Maximum Brightness
At the highest brightness, the dot is quite clear, with no significant fuzziness or other reflective artifacts. At maximum brightness, the CompM4 is just barely visible outside on a sunny day. The CompML3′s maxumum brightness, however, blows the CompM4 out of the water.
When viewed indoors with similar brightness levels, we can see that the sights both produce a nice clear dot. Unfortunately, the reflective red lens coating on the CompM4 is heavier and produces much more blue images than the real CompML3.
The adjustment screws are accessed by screwing off each of the adjustment caps. Although the sight is marked with “UP” and “R” on the adjustment screws, there is no indication of which way they should be turned to adjust the sight up and right. Turning the screws counter clockwise should adjust the sight to up and to the right while clockwise will adjust the sight down and to the left. Once that was determined, the sight is easy to get on target. The screws click into each position quite securely.
Mounting
There are two options for mounting this sight, depending on whether you install the mount spacer or not. The low option is good for guns which have raised sight rails like a G36 or a P90, while the high option is specifically for guns with standard M4-height sights (M4, M16, SCAR, LR-300, etc..).
This allows your sight to ‘cowitness’ your iron sights. In other words, with the iron sights and Aimpoint in place simultaneously, the view through the iron sights should be exactly centered in the lens of the Aimpoint. This is a critical bit of information for those high speed low drag ‘operators’ among us. :P
Most of my problems with this sight are with its mounting hardware. While it is able to clamp on to a rail quite tightly and securely thanks to the over-sized mounting knob, the screws used to secure the clamp to the sight are of the wrong size.
First, the heads of the short screws for use without the mounting spacer are too wide. The screw heads did not sit flush with the bottom of the mount until I dremeled a bit of metal off the rim of their holes to properly counter-sink them.
Second, the shafts of the long screws that are intended for use with the mounting spacer are too long. They bottom out in the sight before they are able to fully tighten down on the mounting clamp, allowing it to rattle quite significantly. I’m sure this can be fixed with a little more dremeling to remove some unneeded length from the screws, but I have not had a chance to complete this task myself.
Conclusion
I hope this did not read too much like a negative review, because this replica really is fantastic. It was bound to come up short when comparing it to a real Aimpoint, but the fact that it keeps up so well is amazing. I have seen both the King Arms and Star Comp M4 replicas, and in my opinion, this is the one to get. While the King Arms replica looks nice, it is powered by three LR44 batteries which, in addition to being quite costly, have a life comparable to the attention span of a elementary schooler with ADD. The STAR replica is powered by a AA battery, but really only looks superficially like the real CompM4. Neither of these have the trademarks that this ACM version does.
Update (7-8-2010)
Due to a total breakdown in the sight’s dimmer switch, I’ve been forced to shelve it for the past few months. Upon taking it apart, I found that the ball bearing that makes contact with pads on a printed circuit board for selecting the different brightness levels had been eating into the PCB material, finally resulting in this failure. As a result, I’m updating the ratings that follow. It’s really a shame that a sight this nice has such a fatal flaw.
Pros:
- Realistic finish & design
- Excellent trademarks
- Easier to use than previous Aimpoints
- Aiming dot is bright, fine and fairly sharp
- Long battery life using cheap, plentiful AA batteries
Cons:
- Neither high-or low mounting is perfect out of the box
- Dimmer knob is finicky, sometimes turning the sight off
- With moderate use, the dimmer knob is likely to fail due to poor design.
- View through sight is overly ‘blue’
- Slight parallax error at lower right edge of scope.
Performance: 2/5
Above average dot & battery life but the dimmer knob can be argumentative and is likely to completely fail in the long run.
External Design: 4/5
It looks and feels spectacular, but the mounting hardware, while fixable, leaves something to be desired.
Value: 4/5
For less than $60 plus shipping from RSOV, this sight is priced right.
Overall: 2.5/5
A solid scope other than the fatally flawed dimmer knob.
Have you used this on a real steel weapon or just airsoft? If so, how many rounds have you put down range in what caliber, and how has it performed?
Unfortunately, this sight has broken down and been shelved since I originally wrote the review. I’ve updated my review and ratings to take this failure into consideration.
Here at Chairsoft Press, many of our reviews are written with consideration given to the fact that the items we review are replicas and not intended for the same level of abuse that the real gear can take. In light of this, I felt that the ACM CompM4 was a good sight considering its cheap price and performance relative to other replicas. However, I would never recommend the sight over a real Aimpoint CompM2/3/4.
I wouldn’t recommend putting an airsoft optic on a real steel weapon ever, in case that was what you’re looking at. 1: It will Not hold Zero at all. 2: These are not made to withstand recoil. If the fake optic lasts more than a few magazines downrange of real munitions, it could count itself among some of the better airsoft Equipment. Best to save your money for a good optic for a real rifle, which coincidentally can also stand up to airsoft use ;)