Thursday, June 20, 2013

Choosing the Right Scout Rifle AR Optic

Choosing the Right Scout Rifle AR Optic
According to the US Army Laboratory Command. (Small Arms Technology Assessment: Individual Infantryman's Weapon, Volume I, March 1990 - to be specific), 98% of all targets across all terrain are engaged at less than 600 meters, 90% less than 400 meters, and in urban terrain 90% less than 50 meters. With this in mind we need the ability to be able to reach out to targets beyond the 15-25 yard lines but it is unlikely we will ever shoot out beyond 600 meters in a defensive or even hunting situation.
Of course this concept loosely dates back to Jeff Cooper's "Scout Rifle" concept where there is focus on lightweight and flexible accuracy. Although Jeff's ideal scout rifle was chambered in a more energetic 308/7.62x51 round, there is no reason not to substitute today’s all purpose AR-15 platform loaded with the best premium ammo. For all manner of critter the AR15 platform is a viable scout rifle option when paired with the right optic as has been proven defensively viable to the 600 yard range by our heros overseas carrying the military equivalent M4 topped with optics in the 4X range.
There is definitely a misnomer that you need very high power optics on any rifle to engage 12" targets at distances out to 600 yards. Most people without military training would be shocked how easy it is with a little practice to hit the 300 yard 12” gong with just iron sights or a simple red dot sight. Beyond the 300 yard mark, just seeing the target begins to become difficult.  Adding even a marginally magnified optic enables more precision, faster target acquisition, and will deliver all you need to place hits quickly even way out there when yards adds up.
More than a few serviceman and Designated Marksman know that the 4X Trijicon ACOG transformed hit ratios within all ranges of combat engagement out to the 600 yard line however it also comes with a steep price tag. The current military demand and the booming civilian 3-Gun competitions have thankfully created a huge market for optics in 1x-6x magnification range.
I asked several manufacturers at this years 2013 Shot show, "What would they recommend for a good quality ‘affordable’ AR-15 scout rifle optic?" and here were the results of those recommendations and my testing/observations of each optic.

TESTING - Although some of the pictures show the optics mounted to various AR15 format rifles, each optic was mounted and tested on my Houlding Precision Custom AR15 with a hammer forged Daniel Defense tapered barrel which has proven itself to deliver consistent 1” - 100 yard groups. Each optic was zero’ed per manufacturer recommendations (usually 200 or 300 yard zeros). Those which did not specify a zero were zero’ed to 300 yards.
Each optic was tested with shots at yardage increments of 2, 25, 50, 100, 200, 300, & 400 yards. Those optics which had open adjustment turrets or a BDC were also shot to 500, & 600 yards. This testing was not designed to collect time-shot data or accuracy analysis, but to provide me with a standard testing platform for the month it took to work through the testing during the day and late into the night. The end result were a number of interesting observations I did not expect.
OVERALL QUALITY - I want to make a few broad statements about all of these fine optics. None of these scopes should be considered “budget models” by any stretch of the imagination.  All of these are high quality, considered military grade rugged, very clear and provided me with an undistorted view at 300-400 yard targets.
For those that like to spin turrets, all of these designed marksman focused optics provided good turret zero repeatability, however some were better than others on ease of use. Most however were designed around a set it and forget zero point versus turret adjustments for longer range shots. Those scopes with larger tubes and objectives seemed to deliver a bit more light to the eyeball, but not to a degree of becoming a major deciding factor for me on any of these optics. The features themselves tended to be the factors which would deliver annoyance or praise based on your needs noting that one man’s ultimate optic is another man’s agony. Find the one you like and learn how to use it with your favorite round and rifle.
ZEROING OBSERVATIONS - Most of these optics were designed around specific 100, 200 or 300 yard zeros. These specific zeroing requirements align to either a flat shooting 200 yard zero profile or to a BDC (bullet drop compensating) reticle. Of those tested here, some use 100, 200, and 300 yard zeros so it is important not to use a standard military 25Y/300Y (25M/300M) zero. A 200 yard zero delivers a more precise 0-225 yard rifle with a bullet path that will vary approximately only 1.5” high at 100 and only 1.5” low at 225 yards. A 300 yard zero will get you out further, however the bullet path will vary considerably more up to 4.5” high at 200 yards to 12” low at 400 which is not the best for varminting or precision shooting but just fine for defensive work. Everything is a compromise and so it is that each of these scopes will perform differently based on the initial zero.
PRECISION - I know folks who can shoot the center out of a dime at 100 yards with iron sights and deliver 300 yard open sight groups that I would have a tough time matching with a 10x scope. If you have the skill and take the time to truly understand the bullet path, these optics will all deliver precision shots, however all were designed for combat/hunting level shots where fast shooting at guessed distance is the norm (the Hi-Lux CMR being the only ballistic calculation friendly exception).
Some of these scopes are designed around a single point of aim with the above mentioned zero which can deliver 0-300 yard shots easily, others use BDC (Bullet Drop Compensating) multiple aiming point reticles which deliver a bit more accuracy at each distance. The BDC hash marks on a reticle will deliver the bullet roughly on the mark. You may get lucky that your favorite .223/5.56 round is spot on to the hash marks, but chances are the bullet will land within a few inches high or low based on your rifle, ammo and/or specifically which ammo the manufacturer calibrated the BDC for. In all cases I was able to make the 12” 100, 200, 300, 400, 500, & 600 yards steels go "ping" using the BDC hash marks supplied on some of these scopes. If precision is what you are after you may want to reach for the high 32x+ magnification range optics to wring out the best your rifle can deliver or use a ballistic iphone or droid app, such as Strelok, to deliver precise holds based on your ammo's data. In any case, scopes topping out with 4X magnification are not about precision groups, they are all about making shots quickly.

VERSATILITY - Obviously these scopes are more than capable to top your 308, 30-06, Mosin 7.62x54R or other ballistically similar rounds which follow about the same flight arch. Drop any of these on a forgotten 308 and you have the makings of a mighty fine scout rifle, however for this article I think the the AR scout concept deserves consideration so I am focusing on what these optics can do for an AR15.
RETICLES - Although all of these scope feature similar clarity and 3X or 1-4x magnification ranges, all have different reticles. Some like the Trijicon and Nikon 1-4 look like standard heavy duplex dangerous game reticles, others feature donut+dot or semi-donut+dot reticles which I believe delivers faster aiming at CQB distances. BDC reticles have become extremely popular but can take a bit of range time to really figure out where your gun actually shoots versus where the reticle says the bullet should land. The most unique optic in this group is the Hi-Lux CMR4 which combines the donut+dot reticle with a Mil grid which in theory has all the Mil points to connect out to over 1000 yards when mounted to a 308.
There seems to be a trade off that if a scope has an illuminated reticle which is visible in daylight then the lowest setting is generally too bright for use in the pitch black night; unless I am rolling back over to my non-magnified Eotech, I have yet to see sufficiently bright daylight illumination which still has a setting low enough for night hunts with the exception of Trijicon’s Tritium/fiber optic illuminated reticle.
Nikon M-223 1-4X20 - MSRP $299.99 
Nikon’s M-233 and P-223 AR-15 focused optic series has been wildly popular since its introduction and continues to be with various magnification ranges designed around the .223 Remington round. What I liked was that they are flexible, rugged, simple and are do not require a math degree to put shots on target when using the turrets. Nkon's optics are very clear and come with a number of features which are usually found on more expensive models.
This optic delivers what almost any 3-gun shooter wants which is a smooth zooming operation, a flexible eye relief window that does not require a perfect mount, and a reticle which is designed around fast defensive and sport shooting.  Nikon’s Point Blank reticle is designed to be zeroed at 200 yards with 100 and 300 yard range zeros being on top of the center dot (100 yards) and under the center dot (300-yards). The 200 yard zero’ed “point blank range”/zero is also coincidentally a 55 yard zero which is super handy to know for for the statical “90% of shots under 50 yards”. Nikon has calibrated the reticle to be spot on with most .223/5.56mm 55-grain polymer tipped rounds such as the popular Hornady 55gr TAP round.
What I Liked - Once you get beyond the 300 yard range or to fine tune zero to a different round, you will start reaching for the turrets. The turrets were a huge feature for me on the Nikon AR optics. The oversized turrets are easy to turn even with gloves and are labeled in ¼” clicks (100 yards) so if you are off at 100 yards by 1 inch, you just turn it the turret “1” mark. If that happens to be the new zero just lift the turret and turn to reset the zero mark - simple. The turret detents clicks perfectly aligned to the turret marks and delivers heavy audible clicks which are very unlikely to be bumped in the field. Optimized for a 200 yard zero instead of a typical 300 yard zero which means 100 and 225 yard holds are just under and over the Point Blank center point. Depending on your ammo, the top of the thick bottom reticle line may put you on the mark at 400 yard mark as well.

With a 1X setting on the dial, this allows a both eyes open shooting style even in sub-10 yard distances with a near true 1X magnification. Nikon has what looks like a polished copper reticle on these scope which picks up light and delivers a very nice glowing effect in direct sunlight which almost makes it seem illuminated. Once in lower light the reticle appears black.
What I Would Change - Illumination would be a nice little add in to improve the optic for low light CQB work. Without illumination, the optics suffers after the lights go out or on dimly lit targets. The Point Blank reticle is great for connecting pretty precisely with anything between 0-300 yards, however I would have liked to see a couple of Nikon’s BDC circles for 400, 500, 600 yard ranges.
What I Would Use it For - Designed for a 200 Yard Zero. 0-300 yard shots in dusk to dawn hunting and shooting and is perfect for 3-gun work and of course offers the flexibility. It is also the lightest variable power tested. For the turrets spinners, this is your scout rifle optic. Expect to twiddle the turrets to get out to the 600 yard line without a BDC. King of flexibility, but the lack of a BDC makes shots past 300 guesswork without spinning the turrets.


Nikon P-223 3-32 BDC Carbine - MSRP $149.99 
This is a compact format fixed power 3X scope and is the quintessential scout optic. The Nikon P-223 3-32 gets the best buy award at a poultry MSRP $149.00.  Goofing around testing various optics at night, this little 3X P-223 was by far the brightest of the pack but without an illuminated reticle, hitting anything is sketchyin the really really dark of night.

Nikon has calibrated the reticle to be spot on with most .223/5.56mm 55-grain polymer tipped rounds such as the Hornady 55gr TAP round. The new BDC Carbine reticle provides a 200 yard zeroed crosshair with "hash marks" at 400 yards and 600 yards.
What I Liked - I am a huge fan of fixed power optics as you don’t have to worry about being on the wrong magnification setting for your BDC to work right and your mind trains itself to range targets quicker than “was that one hash mark tall on 2X or 4X... and of course there is less to go wrong. 

This very small compact scope delivers the shooter 50-600 yard shot placement on 12” targets easily without wondering if ranging is off from the wrong magnification - simple works. Same goes for the great Turret features on this Nikon model as well, however the ticks were just a tad off kilter which annoys me. Nikon has what looks like a polished copper reticle on these scope which picks up light and delivers a very nice glowing effect. Once in lower light the reticle appears black.

What I Would Change - This reticle BDC tree screams for full illumination including a super low night vision setting. If illumination was a $200 MSRP option, this option would be the perfect low cost scout rifle optic. Illumination allows you to trick your eye a bit and would have made this optic a close sub-25 yard CQB optic. Without illumination, really close shots are doable, however it looks like you are shooting giants under 10 yards.
What I Would Use it For - Not the best for CQB shots under 25 yards due to the lack illumination. Designed for a 200 yard zero, with hash marks at 400 and 600 yards. Great for 25-600 yard shots. For this price this is a no-brainer optic purchase and the best deal in a scout rifle optic. Also an excellent predator/varmit optic for a ranch focused AR-15. For the turrets spinners, this is another great scout rifle optic, but due to the BDC hash marks there is no turret spinning required to put shots on 600 yard targets quickly. By far the lightest optic in this test at only 12 ounces. If I was equipping an armory of AR15 scout or ranch rifles economically, all would be wearing this scope.




Burris AR-332 3x PRISMATIC OPTIC - MSRP $349.95 
Burris has been famous for building rugged bulletproof optics. The AR-332 is a mil-spec brute of an optic which has stayed compact with a prismatic design. The design is a really nice crossover optic for CQB and scout rifle distances in a durable fixed power optic. Essentially the AR-332 is an ACOG but for 60% less money plus it includes a dual red/green illuminated BDC reticle. According to Burris they have been selling truckloads of these along with their 5X model. Based on my experience this is for good reason.
At first I was wondering what I had committed to with the AR-332, however after a couple range visits I am sold on the design. The donut reticle definitely grows on you and in my opinion seemed faster than the duplex reticle.
What I Liked - There is a significant amount of refinements and extras on this scope. The AR-332 comes ready to mount right out of the box with a picatinny base included ($50-$100 extra on other scopes here), scope caps that flip open all the way out of field of view, and wire retained windage/elevation caps. On top of those features, the AR-332 is a very clear optic with an etched reticle visible as a black reticle after the illumination is turned off. The run-time is expected into the months range, but even when the standard CR2032 battery is dead you still have 100% of the reticle to work with.
The illuminated reticle running either green or red can be seen in direct sunlight and for CQB use is good at night. The donut reticle is very fast on target even at distances under 25 yards or even at 2 yards. Dedicated points from 100-500 yards can make this a bit more precise than optics with just a non-BDC duplex style reticle or wider dispersed hash marks when the yards add up. If you have an A2 AR15 with a carry handle, the AR-332 will work right out of the box after your unscrew the included picatinny base. Burris also includes picatinny accessory rails around the optic to bolt on things like red dots, lights, and tactical espresso machines. The circle holds marks for 200+ yards work great and allows tiny distant targets to be centered quickly. For around $350 this is a great option to high dollar hard use defensive optic with the flexibility of dual illumination.
What I Would Change - The eye relief needs to be a bit more forgiving as it does not have a wide workable range compared to others here. Plan on mounting the AR-332 almost or at the rearmost position. My stock position is always one detent in, however for longer armed shooters, you may have to displace your rear back up sight and mount it farther back.

I could live without the extra picatinny rails however it makes it look cool and they are easily removed.
Burris needs to add a super low night vision setting for the illumination as even the lowest setting is still just a bit too glary after the lights go out. The reticle is still perfect for CQB ranges at night using the CQB Optic but a little annoying for precision shooting night dwelling critters in the pitch black. For those situations I swapped out to old half dead CR2032 batteries for dimmer illumination.
To make this optic even better, I would add a inverted V to the donut reticle to show typical wind holds.
What I Would Use it For - Designed for a 100 yard zero with BDC for 100-500 yards. This is a flexible fixed power optic that is actually exceptionally good at CQB work thanks the that glowing donut.  

A great all purpose defensive and dangerous game optic for an AR owner to extend the range of their AR. That big glowing dot provides a great aiming point even at room clearing distances. The more I use this optic the more I like it as a combat defensive scout optic covering 90% of the US Small Arms study ranges.




HI-LUX/LEATHERWOOD CMR4 (CLOSE TO MEDIUM RANGE) 1-4X24 - MSRP $525.99 - Leatherwood has a long storied past which dates back to one of the most well regarded sniper optics ever used by the military. Today they make some very high quality optics at prices which are about half to a third of comparably clear and bright optics. The old Hi-Lux/Leatherwood CMR had all the bases covered with BDC hashes from 0-600, but the new version has expanded MRAD grid marks which can take you all the way to 1000 yards if you have the skill.  Last year Hi-Lux updated the CMR with the above improved reticle, and moved the turret windage adjustment to the left side so you don’t need to lift your firing hand off the grip to make adjustments.
Other updates includes adding turret caps which cover full sized turrets.  A ton of refinement has gone into this optic and the stunningly useful reticle which delivers both a quick shooting CQB semi-donut and hash mark options to 800 yards and MRAD precision increments. The CMR4 delivers an impressive amount of Mill-based data to the shooter in an affordable 1-4x optic. Other new features are the Mil adjustment turrets, 0.1 Mil per click, and 80 clicks per revolution.

What I Liked - The Hi-Lux CMR4 illuminated reticle is available is your choice of red or green illumination however the reticle is visible without the lights on. The CMR is the only optic in this price class that offers a kick ass turret design with both resettable zero and a zero stop. Yep you got it, find zero, lock it in and no matter where you end up on your turret spins, you will always be able to return to zero even in pitch black by spinning back to the hard stop.
The movement of the windage adjustment to the left side is a brilliant idea which works and allows your support hand to handle the windage work. I had the old CMR and loved it, but the new CMR4 is improved with a two additional night vision settings for glare free shooting in the dark of the night and an an improved reticle. Crank up the illumination and you have an outstanding CQB optic. If you are a ballistics nerd like me, this reticle has it all satisfying CQB to long range hit capability. Hi-Lux has made the marks faint enough that they do not get in the way, but are visible enough when you need them. Hilux has even included flip up scope caps.
What this grid of Mil data provides is 40 mils of hash marks of elevation and windage left/right and the unique ability among the optics here to use a ballistic calculator accurately to place shots all without touching the turrets. Admittedly this is my 1-4x24 optic utopia.
What I Would Change - With the exception of including a set of extra high rings, Hi-Lux has pretty much hit the nail on the head for me. The one observation is that illumination is tuned for low light to total blackout but is not visible in bright daylight; not a big deal for me, but some might expect a big glowing dot during daylight. If you are not into the whole nerdy ballistic calculations thing, then the reticle may be a bit crowded and you might want to lean to a simpler reticle design. The CMR4 needs a super bright illumination setting for bright daylight use. The illumination is definitely designed for CQB, low light and night work. The magnification adjustment ring is Zytel where the others are all metal.
What I Would Use it For - Great on .223 or .308 platform for precision work with a low power optic. All purpose shooting from defense, to varmit, to hunting, to scout rifle work. The partial donut-dot makes a good CQB reticle. It also has enough data to keep the serious data driven shooters happy and has the precision to deliver incredible groups even at stunningly long ranges.


MILLET DMS (DESIGNATED MARKSMAN SCOPE) 1-4X25 - MSRP $229.95 - The Millet DMS probably was not the first 1-4x Military Marksman focused optic, however it is known as the original 1-4 Designated Marksman Scope.  Today, the DMS still offers great features all while being one of the least expensive illuminated 1-4x optics designed for military use. I bought one  Where the Millet DMS differs is that it pushes strongly into the CQB realm with a glowing daytime visible 18 mil donut with one mil center dot. The Millet offers good clarity and is built like a Abrams tank and is also the heaviest at 18oz; about 4-6 ounces heavier than any other here.  
The DMS is designed as a set it and forget it zero however nothing I could find pointed out at what range it was optimized for.  I used a 300 meter zero which made hits on anything from 2-400 yards easy, beyond that some math was involved to hit the 500 and 600 yards gongs.
What I Liked - Like other illuminated reticles, the DMS reticle is black once the illumination is turned off. The reticle is a simple 3-400 meter completely uncluttered CQB reticle design that is very simple to point and shoot. I have used this optic on everything from 308’s to 22LR and it has held up very well over the last three years of use on a wide array of rifles. A daylight tuned optic with a dright donut visible in daylight. The design is brilliantly simple and effective. I would venture to say this may be the most durable 1-4x optic available however not the most clear and not the biggest field of view. One feature I wish every illuminated optic had was the extra battery Millet hides under the windage cap... neat feature.
What I Would Change - Millet needs to add a super low night vision setting for the illumination as even the lowest setting it is a bit glary in the black of the night on critters.The DMS does have a number of Mil based calibration points, however it requires a learning curve and is far from an intuitive reticle to use for quick BDC type shots beyond 400 yards. 
Millet may want to update this optics with a few BDC marks, and improve the clarity a bit, although it was arguable the first 1-4x DMR scope, it is probably time for an update as other more feature rich competittors are closing in on Millets sub-$230 price point.

What I Would Use it For - Although I think the scope needs an update, it is a heavily used optic for me. Its reliable and holds zero perfectly on everything from .22LR-.308 rifles.  In short, if you plan on beating the crap out of your rifle and optic, the Millet may be a great option. Also one of the least expensive quality illuminated optics available.

I would use this as a CQB focused optic from 2-400 yards. It delivers a clutter free donut reticle design in a flexible variable power optic that can take a serious beating.

TRIJICON ACCUPOINT - 1-4x24 TR24-3 - MSRP $1050 -
By far the most expensive optic reviewed here, the Trijicon Accupoint is what most think of as a dangerous game designated marksman scope. Part of that rationale is the high optic clarity and the dual illumination. During daylight hours the fiber optics deliver a brilliantly bright yellow dot in the center of the standard duplex reticle. 


The intensity can be adjusted with a slide cover near the eyepiece. In the dark of the night, the Tritium takes over and delivers that same yellow dot for around ten years and then starts to fade slowly. In reality I have never heard of anyone actually replacing their Tritium yet. The Accupoint is a set it and forget it zero point which I choose to zero at 300 meters.  Beyond 400 yards the lack of a BDC makes 500-600 yards hits guesswork.
What I Liked - It is the only optic’s illumination here which excels at both night and day operation, even in total blackout conditions. It is light, very clear, and provides a simple but effective duplex reticle which makes use a simple and easy affair for newer shooters. I picked up my optic used and the front of the objective had been slightly crushed from an over aggressive ring tightening from the previous owner. I have never had an issue, so Trijicon must have engineered it to a thickness that still protects itself from owner stupidity.
What I Would Change - It needs to be less expensive.  I am all about buying Made is USA, however at $1000 it is three times the cost of its next closest competitor and this is not exactly a new optic... maybe time for a price adjustment. The technology around battery powered competitors allows for 4-6 month run times on a $5 battery, so I am not sure Tritium has a huge advantage any longer, but it was the only optic which beat every other optic when it comes to flexible illumination.
What I Would Use it For - This is a really flexible optics for any use from 2-400 yard ranges. The excellent illumination is perfect for day or night and even makes this a very good CQB optic. If you have the cash, the Trijicon does delivers the best illumination here, however the optics clarity are similar to the Nikons, Burris, and HiLux.


CHOOSING THE RIGHT SCOUT RIFLE OPTIC FINAL THOUGHTS - In today’s market, there a load of choices including some great brands that are not included here such as Leupold and Vortex with a multitude of models which could also have been included here, however the point of this review was to understand the advantages of each of these uniquely different optics.
Each of these optics has its focus, no pun intended. Generally speaking I would not choose one of the CQB focused designs for a distance focused precision scout rifle. The same could be said that the CQB focused reticles were better at closer shots because big illuminated donuts come onto target faster. Everything was a compromise on every optic. Sure I have my favorite, however I know others who have noted the Hilux reticle is a bit noisy for them, where I have wanted for more information on the Burris and Millet reticles.  The Nikon's are both a great value and the 3X has become a favorite of mine. There are no bad choices here, however I do hope I have brought your attention to little things that allow you to find the optic that fits your needs for your AR15.
AN ODD OBSERVATION - We all get older and usually with that comes deteriorating eyesight. I have been incredibly lucky that I still have crystal clear 20/20 vision, however I am starting to do that trombone move to focus in on the small print up close. The point is that magnification and sighting aids help ageing eyes. A few of my buddies clearly need magnification and this is where even just a little 3X magnification can make all the difference between making a shot and frustration at the hunt or at the range. If you are older, I recommend strongly taking a look at what these low power optics can provide you and your AR platform.
CQB OPTIC TIP - For those optics with illuminated reticles, a tip to use them in a CQB environment is to cover or close the front scope cover and shoot with both eyes open like you would with a red dot.  With the scope objective cover in place, your eyes and brain will figure it out and make the illuminated reticle appear as an 1X lit reticle regardless of the magnification even if it is a 32X power scope.

SPECS
Nikon M-223 1-4X20 Scope Specifications
Reticle Point Blank
Magnification 1-4x
Objective Diameter 20mm
Exit Pupil 4mm
Field of View @ 100 yds23.1-92.9 ft @ 100 yds
Tube Diameter - Other 1 in
Eye Relief 4-4.1in
Objective Outside Diameter 25.4mm
Eyepiece Outside Diameter 41mm
Weight 13.93 oz
Overall Length 10.35 in
Adjustment Graduation - Other 1/4 in
Max Internal Adjustment 120 MOA
Parallax Setting - Other 100 yds
Waterproof/Fogproof Yes
Light Transmission - Other Up to 95%
Supplied Accessories Nikon flip-up lens caps. Nikon windage and elevation caps.
MSRP $299.99
Nikon P-223 3-32 BDC Carbine Scope Specifications
Magnification 3x
Objective Diameter 32mm
Exit Pupil 10.7mm
Field of View 35.6 ft @ 100 yds
Tube Diameter - Other 1 in
Eye Relief 3.4in
Objective Outside Diameter 39.3mm
Eyepiece Outside Diameter 41mm
Weight 12.2 oz
Overall Length 8.1 in
Adjustment Graduation - Other 1/2 in
Max Internal Adjustment 100 MOA
Parallax Setting - Other 100 yds
Waterproof/Fogproof Yes
Matte Finish Yes
Use Centerfire Short/Mid Range
AR (Modern Sporting Rifle)
Reticle BDC Carbine
MSRP  $149.95
MILLET DMS - MSRP $285.9918 MOA donut for rapid target acquisition at ranges as close as 3 meters.
Illuminated dot reticle allows you to see your target clearly in low-light conditions
1 MOA dot for optimum medium- to extended-range precision out to 500 yards
Magnification: 1-4x
Objective Diameter: 24mm
FOV @ 100 yards: 23’ @4x and 90’ @1x
Item     BK81002

Weight 18oz
Power/Obj     1-4x 25mm
Tube     30mm
Reticle     Donut-Dot
Lens Coating     Fully Coated
Eye Relief     3.5"
Finish      Matte
MSRP $285.99
Burris AR-332
Item # 300208
Reticle  Ballistic CQ
Finish Matte
Features - 1.5" sunshade and a Picatinny rail mounting bracket, integrated lens covers, also mounts on an AR carry handle
Field of View (in feet @ 100 yards) 32
Click Value (in MOA)  .33
Max Adj.(in MOA)  60
Height above rail (in.) to optic centerline  1.65
Length (in.)  5.29
Weight (ounces) 14.2
Magnification     1x-4x
Objective Size     24
Bullet Drop Compensator    No
Length (In)    10.3
Weight (oz)    14.4
Illumination Source    Fiber Optics & Tritium
Reticle Pattern    Germand #4 Crosshair
Day Reticle Color    Amber
Night Reticle Color    Amber
Eye Relief    3.2
Exit Pupil    17.5 to 5.1
Field of View @ 100 yards (ft)    97.5 to 24.2
Adjustment @ 100 yards (clicks/in)    4
Tube Size    30mm
Housing Material    6061-T6 aluminum, hard coat anodized per MIL-A-8625, Type III, Class 2 dull& non reflective
Adjustment Range    ± 45 MOA (± 13.3 mils) minimum
MSRP $349.99
HI-LUX/LEATHERWOOD CMR (CLOSE TO MEDIUM RANGE)
Tube Diameter: 30mm
Adjustment Click Value:
0.1 Mrad
Exposed Turrets: Yes
Finger Adjustable Turrets: Yes
Turrets Resettable to Zero: Yes
Zero Stop: Yes
Turret Height: Medium
Fast Focus Eyepiece: Yes
Lens Coating: Fully multi-coated
Warranty: Limited lifetime warranty
Lens Covers Included: Yes
Magnification: 1-4
Reticle Construction: Glass-etched
Reticle: CMR Ballistic Reticle
Illuminated Reticle: Yes
Battery Type: CR2032
Holdover reticle: Yes
Reticle Focal Plane Location: 2nd
Parallax Adjustment: No
Finish: Matte
Water/Fogproof: Yes
Shockproof: Yes
Objective Bell Diameter: 30mm
Ocular Bell Diameter: 39.6
Eye Relief: 3"
Max Internal Adjustment: N/A
Exit Pupil Diameter: 11.1-6mm
Weight: 16.5 oZ
Field of View at 100 Yards:
94.8' @ 1x
26.2' @ 4x
MSRP $525.99

TRIJICON ACCUPOINT - 1-4x24 TR24-3 - MSRP $1050 -
Magnification     1x-4x
Objective Size     24
Bullet Drop Compensator    No
Length (In)    10.3
Weight (oz)    14.4
Illumination Source    Fiber Optics & Tritium
Reticle Pattern    Germand #4 Crosshair
Day Reticle Color    Amber
Night Reticle Color    Amber
Eye Relief    3.2
Exit Pupil    17.5 to 5.1
Field of View @ 100 yards (ft)    97.5 to 24.2
Adjustment @ 100 yards (clicks/in)    4
Tube Size    30mm
Housing Material    6061-T6 aluminum, hard coat anodized per MIL-A-8625, Type III, Class 2 dull & non reflective
Adjustment Range    ± 45 MOA (± 13.3 mils) minimum
SOURCES
Hi-Lux Leatherwood Optics - http://hi-luxoptics.com/

Tuesday, June 18, 2013

Troubleshooting Your AR Build

Troubleshooting Your AR Build
At this point I have completed dozens of AR builds from standard .223, 5.56 Nato, .223 Wylde and even a few in the 308 and 7.62x51 chambers. I will say none have gone together perfectly however a few tips and tricks along the way have helped me get a bit smarter with each build. Experience does breed success and thus the reason I believe a defensive firearm you will bet your life on should be built by a professional. Following are a number of tips and tricks which in sum should resolve or prevent the vast majority of AR format functioning issues.
UNDERSTANDING THE ZEN STATE OF AR FUNCTIONING
The AR format is by its nature a much more complex machine with more design similarities to an engine than a bolt action rifle. The gas pressure operated system can be a bit finicky and can also be the main cause of problems.  Including myself, many an expert has professed the reliability improvements of heavy buffer springs, carriers, and buffers, however now with more experience, I have seen that these are just band aid solutions to an over-gassed or poorly designed gas system. Other times problem resolution can be as simple as just swapping out a magazine or part, so lets take a look at some best practices to avoid problems in the first place.


A lot happens as the trigger is pulled, the hammer drops, hits the firing pin which sets off the primer and charge. The pressure in the cartridge pushes the bullet down the barrel and after the bullet passes the gas port, gas is leached off and blown back into the bolt via the gas block, gas tube, and gas key on the carrier. Pressure increases and pushes on the gas seals in the bolt which unlocks the bolt and cycles the action.  A lot can go wrong in that entire process.


Always keep in mind that the AR15 was designed to run with a 20” barrel with a rifle length gas system and full rifle length buffer tube, spring and longer & heavier buffer. By moving to a shorter carbine gas system and buffer tube assembly we are not exactly helping improve performance, recoil, or reliability but instead making it harder for the system actually do its job in a shorter overall system.

DIRECT IMPINGEMENT SYSTEM VS. PISTON 
For a AR builder, I would stay away from piston systems unless they are purchased as a complete working upper or complete factory rifle such as the Ruger SR556. Piecing together a pistol system is asking for problems as they are more complex and a bit trickier to tune than direct impingement system. I have friends who are still chasing around issues with poorly designed or assembled piston rifle kits which, in their case, would only properly cycle full power NATO 5.56 rounds. For the scope of this article I will focus on standard AR15 style direct Impingement gas system rifles as they are far more popular for the masses.
GAS ISSUES 
Nope, Beano will not work in this case. One of the most common causes of problems on the AR format are those related to the gas system. Too much gas ends up battering both you and shortening component life, but too little affects functional reliability.
Too Much Gas - An overgassed/high gas pressure driven system is generally balanced out by heavier components at the breech end to slow the cycling down. The result is that we upgrade from a standard buffer to a heavy “H” marked buffer, heavier “H2”, and even very heavy “H3” buffers and marginally heavier M16 bolt carriers.  All we have done is increase the reciprocating mass to the point where the gun cycles properly and less violently. Sure the heavier components balance things out, however too much hot gas means more overall stress on all components and more dirty hot gas in the action which equates to a hotter and dirtier gun; not to mention an overall heavier gun in the process.
    
Cause - The cause is usually an oversized barrel gas port diameter due to a “better safe than sorry” manufacturing model of most barrel companies. The thought process is that too much gas pressure will always function, to little could cause functioning issues with certain components.
    
Solution - A solution is the above heavier BCG, buffer spring, and/or buffer, however the best solution is to control the gas pressure with an adjustable gas block such as those from Syrac Ordnance, Precision Reflex, and JP Rifles. I stand by the comment that this is the single best upgrade you can make  to an AR15. Recoil, muzzle rise, component wear, and filth all go down and the rifle runs a little cooler and cleaner. Once you are able to control the gas pressure, you can do some really cool things like further reduce gas pressure when using a lightweight BCG from YM or JP Rifles with a standard buffer all without affecting reliability. 
Adjustable gas block are the key is to bring things in balance . See my Adjustable Gas block article here for tuning how-to. Basically keep reducing gas pressure with your lightest load until the bolt does not lock back and then increase the pressure setting by a quarter turn. The need for a heavy bolt carrier is instantly myth busted once your are able to adjust the gas pressure and balance the system.
Too Little Gas - This will cause short stroking, double feeds, failures to feed/extract/lock-back, and stovepipes.
    
Cause - System diagnosed as under-gased are usually the result of improper assembly, however binding components, too heavy of carriers, springs, or buffers or other design issues can exaggerate or imitate an under-gased system. There are certainly fixes which do overcome many design or functional issues caused when fielded, however addressing the root cause is the best route to a durably reliable AR.
    
Solution - In almost all cases the gas block port is not aligned to the gas port in the barrel due to flexibility provided for various gas block. Usually the perfect gas block placement is not slammed up to the turned edge on the barrel.  Disassembly and reassembly with a set of calipers to measure where the hole is on the barrel in relation to the hole on the gas block. Remember usually the rearward most retainer screw on the gas block aligns with the hole in the gas block. One trick during assembly is to install the gas block upside down before installing the gas tube to find the exact positioning of the gas block from the shoulder on the barrel.
BOLT CARRIER PROBLEMS
Smooth Movement - An easy quick check after each cleaning is recommended. Occasionally you will have a BCG that binds for one reason or another which definitely affects functioning. Point your unloaded AR upper skyway and bounce the bolt up and down in the receiver a couple time to simulate cycling. This simple little test will tell you if something is binding. Rarely you might have an out of spec carrier, or loose gas key, but it could also be some junk or a partial brass case stuck in the receiver.  Clean it out and replace parts as required.



Bad Seals - Rarely an issue. Those little seals on the bolt do wear out eventually or can become aligned in such a way that they will leak.  Assure all the cuts are not aligned and/or replace as necessary.
Ejector Tension - Generally a problem that will have even the experienced guys in the crowd throwing their hands in the air and selling off a great gun. Brass should eject at about 2-3 o’clock and about three feet from the side of the gun. If they are hurling 10+ feet away and you start to have feeding/functioning/ejection issues about halfway through the mag, then an over-tensioned ejector is probably the issue.  The military went to a higher-tension/stronger spring to improve full-auto fire functioning with M16 carriers, however in most cases too strong of an ejector spring will not allow a round to properly feed on the bolt face and/or from a timing perspective cause the cases to attempt to eject before they clear the port. The result more often than not are double feeds or failures to fully or partially eject. Most people think they need a stronger spring if they see this and it is usually quite the opposite.
    
Solution - If the ejector cannot be pressed in slightly with the fingernail into the bolt, then it is probably too tight. Another test is to remove the bolt and place an empty case in the extractor lip and lever it down on to the ejector; in some cases I have seen that the ejector is so strong that the extractor cannot hold the brass in place. Remove the spring and either grind it down or swap to a shorter ejector spring. I know the DPMS 308’s have two different ejectors; one version puts way too much tension on the same spring length. The general rule is that if you cannot re-install the ejector without using a tool to push it in, then it is too strong.
Loose/Leaky Gas Key - Rarely an issue. Gas Keys do come loose rarely. Inspect the carrier end-to-end during cleaning. If it is loose, use permanent Loc-tite (Permatex gasket sealer is Mil-Spec) and tighten it back down.
Bolt Bounce - This is a situation where the bolt bounces slightly after it chambers a round because the bolt is moving too fast due to excessive gas pressure and/or to strong of a buffer spring. Without super high speed video equipment, this almost impossible to witness with the naked eye, however it can occassionally be experienced during really fast shooting. This is experienced in the form of a failure to fire with the hammer dropping. Basically it is a timing issue when the bolt is bouncing out of battery at the moment the hammer drops and the firing pin hits air or a partially chambered round. If you are seeing bulged cases at the based or nice heavy primer strikes on the primers and then a light strike and failure to fire during high rate firing, then you may have a bolt bounce issue.  The solution is to move to a heavier carrier or buffer or reduce the buffer spring tension or gas pressure level with an adjustable gas block. Generally the adjustable gas block is the easiest and least expensive solution.
Bolt Not Locking Back - Check the gas block alignment and assure there are no gas tube obstructions. Stick the straw of a WD-40 can down the gastube and if it comes out the barrel roughly the same rate as your are spraying it then you are OK in most cases. What to watch for is WD-40 sprayed in one end and it dripping slowly out the other. If so check the alignment and gas tube. For the most part, AR15s, especially carbines are seriously over gased to the point most will run even if half the tube or port is covered. The most common problem is that the gas block is not even close to being properly aligned with the barrel's gas port.  Although rare, sometimes a builder will have the rear vent hole sealed on the tube and.or have used a 308 buffer and buffer spring or rifle length buffer and/or spring in a carbine or an H2 or H3 buffer which can retard the bolt so much that it cannot fully cycle or lock back. See the buffer weights and measures data below to the right buffer components.
One part which has given me problems is actually the bolt catch. I have installed and tossed a couple out-of-spec loose bolt catches. If the bolt catch is not decently tight, I have had issues with them not catching a bolt on occasion.
POST ASSEMBLY INSPECTION
This may seem like an obvious step, however I have caught more issues in this step than any other just with close examination of an empty unloaded AR all under the assumption that “Stuff works loose.”
Assure the flash-hider, buffer tube castle nut are both tight and secured with Loc-Tite. Are all the pins and detent present, does the trigger function correctly even when holding the trigger down and hand cycling the bolt to imitate the next round cycling? When you point the muzzle skyware on a separated upper receiver, does the bolt float effortlessly without bind as you bouncing it up and down into the chamber by hand?
SELECTING PARTS 
Typically builders get all emotional about what they want based on whatever their buddy or the latest expert recommended, however the reality is that most of the components do not increase reliability, but some do such as an adjustable gas block. Stick with Mil-Spec components if you are focused on reliability as high tolerance “3-Gun” performance parts may throw off the operational balance of an AR without a little tuning/tweaking.
In general every upper or lower receiver I have ever tested has functioned perfectly. The upper or lower receivers have never been a root cause of any issue I have ever experienced, nor the buffer tube, gas tube, stock parts kit, or the furniture, so choose what you like.
Barrels for the most part have not delivered issues themselves regardless of chambering or the finish of the feed ramps, however gas port diameters do vary which can create gas pressure issues. From my experience, pressure problems related to the barrel and gas block have been responsible for well over 95% of my functional issues. The other 5% of issues can usually be tracked to the buffer spring and buffer rates and weights.
STANDARD BUFFER & SPRINGS WEIGHTS & MEASURES (all values approximate)
AR15 RIfle - Buffer 5.2oz, 5.905” - Spring 44 coils, uncompressed 12.75”
AR15 Carbine - Buffer 3.0oz, 3.25” - Spring 39 coils, uncompressed 11.25”
AR10 Rifle - Buffer 5.4oz, 5.215” - Spring 34 coils, uncompressed 13.75”
AR10 Carbine - Buffer 5.4oz, 3.26” - Spring 34 coils, uncompressed 13.75”
DPMS 308 Rifle - Buffer 5.3oz, 5.31” - Spring 39 coils, uncompressed 12.75”
DPMS 308 Carbine - Buffer 3.4oz, 2.48” - Spring 27 coils, uncompressed 11.5”
AR15 Carbine Buffer Weights - STD 3.0oz, H 3.8oz, H2 4.6oz, H3 5.4oz
Note - Super special extra heavy buffers (H2, H3) and springs have caused me nothing but problems with anything but full power Nato spec ammo.
THE STANDARD DIRECT IMPINGEMENT GAS LENGTHSA general formula for barrel/gas system configuration is: sub-16” barrels should have carbine gas systems, 16”-18” barrels with Mid-Length gas systems, and 18”+ barrels with rifle length systems. Obviously there is some leeway, but a 20” barrel with a carbine system will probably be way over gassed and a 16” barrel with a rifle length system will generally have some under-gassed cycling issues.
Even with a properly designed system an adjustable gas block will help you fine tune the system. Once properly tuned, it will deliver you a stunningly near recoilless and reliable shooting rifle all without adding weight to your action or without changing any other components.
GRIP/DETENT SPRING
Grip Spring & Detent - Almost every AR owner at some point swaps their grip, however nearly every grip swap virgin usually also ends up on all fours looking for the grip spring and detent after pulling off the grip. … and then ends up having a crunchy sounding selector when reinstalled.  It should be noted that the grip itself partially holds the spring for the selector switch and the other half of the spring extends up into the selector detent hole pressing against the detent. Watch how it comes apart and prevent either crushing the spring during install or the dreaded boing of the spring across the room. 
MAGAZINES
Generally I have not had any problems with USA made steel, stainless, or aluminum magazines or with Troy’s and Magpul’s polymer mags. Other mags work well also, however I would note caution as there has been a flood of really crappy mags hit the market which I personally would run from. European mags are less forgiving than US mags as they adhere to a very tight tolerance level. Most 30-round Euro mags, such as E-Lander, are designed for a standard 28-round military spec magazine load to assure positive reloads on a closed bolt.
As any military trained person and they will tell you they only load 28-rounds in a 30-round mag just to assure positive reloads. USA mags in general are designed around the “US consumer” expectations to load a full 30-rounds, however the Euro mags are not. Also euro spec AR15 receivers are less sloppy than to what many US manufacturers adhere to, which in the end means that a Euro mag may be a bit too tight to properly cycle. Be safe and load 28 and you will have far less issues overall with any mag you use.
First and second generation DPMS 308 factory mags are specifically problematic and contribute greatly to feeding and functioning issues. With a few modificaions they can work fine, however in general, I have swapped to Magpul LR-20 magazines which have resolved a great number of 308 related functioning issues.
AMMO
Some ammo is shit and will cause feeding and functioning issues. Specifically I have tested and proven to myself that Herter’s 62gr .223 Remington rounds are underpowered. If you want to have a bunch of jams, but this stuff. In most other cases, I have not had any significant issues with any other ammo. My favorite plinking/fun ammo has become the American Eagle 55gr and Hornady Steel case which is sadly temporarily discontinued.
FINAL THOUGHTS
My hope is this prevents some great ARs from being sold or pushed to the back of the safe.