You Don’t Need Them, But You Need Them

Back-up sights. For every guy who tells us they aren't needed, there's somebody else who tells us about the time their brother's, girlfriend's, sister's, boyfriend's optic took a bullet and he was forced to use his flip-up sights.

We're still looking for that dude for comment. But, in the meantime, we reached out to three other guys with some verifiable down-range experience and asked them their opinion on back-up iron sights.

J.D. Potynsky is the CEO of Northern Red, LLC and a veteran of the 3rd Special Forces Group. The man has racked up multiple combat deployments and now runs a company that disseminates what he and his teammates learned in combat.

Potynsky recalled one incident when he had to shoot a vehicle speeding toward the checkpoint he was manning. Things went from boring to adrenaline dump quickly and offered Potynsky no time to prepare for the engagement. He raised his rifle to address the threat, but the battery saving feature had shut his EOTech off. With no time to push buttons or flip up the iron sights, Potynsky relied on muscle memory and shot using the window of the lifeless optic and the front sight post on his M4 to hit the vehicle.

“I couldn't have gotten up a back-up iron sight,” said Potynsky, “there wasn't enough time.”

But, just as Potynsky explains his one chance to use BUIS was gone before he realized he needed them, he's also not ready to call them useless.

“There's an immense amount of pressure to not be that guy,” says Potynsky. “Because if you're the guy that falls out of the truck on infill and something breaks, it's irresponsible not to have irons on your gun. Professionals probably wouldn't go out without them.”

Frank Proctor is the founder of Way of the Gun and an 18-year Army veteran with 11 of them in Special Forces. He spent a couple years teaching the Special Forces Advanced Urban Combat Course.

“I've not seen an optic fail. And, I've never experienced a failure that could have been fixed by back-up irons,” says Proctor, “It's just added weight and expense, and I don't put them on my gun unless I'm only shooting irons.”

But, he knows guys will use them no matter what he says. Whatever sights you choose for BUIS, he says make sure they don't handicap your ability to use a primary optic. “I've seen guys with ACOGs pushed forward to accommodate flip-up irons,” he says, “but that thing should be mounted all the way to the back to be effective.”

On the flipside, Paul Howe, owner of Combat Training and Tactics, an Army special-operations veteran, and a team leader during the 1993 Battle of the Black Sea in Mogadishu, says learning to use irons is essential to competent weapon operation.

“Iron sights have never failed me in combat or on a flat range,” says Howe. While he generally shoots a 3x magnified optic outside of the schoolhouse, he says, “I shoot iron sights when teaching my classes to show students it can be done.”

He also expects his students to run irons and doesn't give alibi shots if a student's optic fails during a qualification course of fire. “I expect them to finish the course of fire with their irons,” says Howe, “just like I would expect them to do in a fight for their life.”

All three guys agree that whatever aiming systems you have on the gun, you must practice equally with all of them to be consistent and accurate. So, if you decide to add BUIS to your gun, plan on training with them as if they're your primary system, so that you're not fumbling, physically or mentally, when the time comes to go to your back-up sights.

Sight Heights

A standard AR sight plane is 2.6 inches above the bore, the height of an M4's front sight base. Whether rail or barrel mounted, standard height AR/M4 sights line up with this sight plane. Any standard-height sight should work with any other standard-height sight, as well as a standard front sight base. Guns with taller rails, or lower stocks, such as HK 416s and SIG 556s, require shorter sights.

If you've heard the term co-witness used to describe sights, it's likely being used to describe the height of a red-dot sight mount. Absolute co-witness refers to an optic mount that places the reticle in line with the standard AR sight plane. Absolute co-witness irons will obscure the bottom of the optic's view.

Lower third co-witness refers to an optic mount that places the reticle just above the standard AR sight plane. When looking through an optic mounted with a lower third sight picture, irons occupy a smaller portion of the sight picture beneath the reticle than absolute co-witnessed sights.

Be aware that the multitude of iron sights heights can produce high, absolute, lower third, and even no co-witness with a standard-height optic mount, so pay attention if you're mixing and matching irons and optic mount heights.

Our advice is to keep things simple when running optics and irons on an AR. You've got the best chance of getting what you want if you stick with standard height AR sights and choose an absolute or lower-third co-witness optic mount.

Apertures

In general, the rear sight of an AR has a rotating aperture leaf. The smaller aperture is usually 0.07 inches and is the go-to aperture for zeroing and normal shooting situations. The larger aperture is 0.2 inches and is useful when you need more situational awareness, such as shooting things up close, movers, or when visibility sucks.

Iron Sight Pictures

We consider the standard sights for an AR to be those found on general-issue military carbines. This is the goal-posted, dual aperture leaf in the rear and a sight post inside a “Y” up front. The most common sight variation you're likely to see in the USA is the HK-style front sight, which replaces the M4-style front sight arms with rounded arms that many find easier to line up with a round rear aperture.

Beyond the basics, there's a ton of options for iron sights. Ghost rings and open top sights are at home on shotguns and in cowboy movies, not ARs. Modern rear sights can have round, square, diamond-shaped apertures with any number of things going on around them to help speed up sight alignment including, painted lines, barbs, and tritium inserts. Up front you can find white and colored sight posts, chevron markings, fiber optic and tritium inserts, and plenty of other useful and useless novelties.

Inline or Offset

Far from the last consideration when it comes to irons, but the last one we've got room to cover, is inline or offset. Running a flattop rifle with an unmagnified (red-dot) optic? Take your pick. This combination allows the use of inline BUIS with the primary optic still in place, as long as a lens isn't smashed or fogged up. If you've got a QD optic mount, you're still in business with an obscured optic. If not, you better hope you've got a wrench, or offset irons.

Offset irons are great as a back-up for a magnified optic and as a second set of sights for targets too close for the primary optic. Roll the rifle so the sights are plumb to the bore and carry on. Precision guys without a Pic rail, don't feel left out; we've got offsets that mount directly on your scope tube.

When it comes down to it, it's on you to decide if saving 4 ounces is worth the risk of being that guy.

WM Tactical TUOR MKII Locking Iron Sights

Weight: 2.86 oz / 81 g (set)

Front Height: 0.67 in / 17 mm (stowed)

Front Length: 2.17 in / 55 mm (stowed)

Rear Height: 0.67 in / 17 mm (stowed)

Rear Length: 2.28 in / 58 mm (stowed)

Sight Adjustment:

Front: Elevation – A2 front sight post tool

Rear: Windage

Lock: None

MSRP: $199

URL: www.wmtactical.com

411: The original TUOR, the Latin word for sight, multi-axis iron sight was a novel approach that economized budget and rail space by combining regular iron sights with offset irons in a single package. The MkII version of the sights improve on the original by adding a locking mechanism to the lateral axis. To employ the sights as standard flip-up BUIS, just flick the sight arm up. If you need to see around an optic or an optic base, push the arm into the base to unlock the arm and rotate it into an offset orientation. You can use them on either side, which could be handy in some confined spaces… if you have time to move the sights before the engagement begins. If you employ them after an optic failure and you can get the optic off the rail, you can rotate the offset sights back upright, should you choose. Also very neat. The caveat comes with the height of the bases. That rear sight is tall when folded down and its arm can't be rotated into the offset position with large magnified scope bells or low-mounted optics that hang over the top of the TUOR. For instance, the sights worked fine with our Aimpoint Micro T-2, but the arm wouldn't clear the ocular bell of our Leupold Mark 6 3-18. WM Tactical has a chart you can ask for to determine if your optic will clear their sight. A non-issue that's sure to come up is the sight system's odd offset from the bore axis when rotated. When rolled to the side, the barrel isn't plumb from the sights. It's 1-inch by 1-inch offset from the bore. It's not a big deal. Don't overthink it. Targets up close will get the news, distant targets will still get the news maybe an inch or 3 to the left. For one thing, you're still shooting irons. And, you're still within the cone of accuracy limits for anything but a pulsed plasma rifle in the 40-watt range.

BoBro Engineering LowRider BUIS

Weight: 1.73 oz / 49 g (set)

Front Height: 0.20 in /5.1 mm (stowed)

Front Length: 2.24 in / 56.9 mm (stowed)

Rear Height: 0.20 in / 5.1 mm (stowed)

Rear Length: 2.31 in / 58.8 mm (stowed)

Sight Adjustment:

Front: Elevation; Custom tool.

Rear: Single aperture. Windage; Hex key.

Lock: None

MSRP: $200

URL: www.bobroengineering.com

411: Some optic and rifle combinations are just a pain in the ass to get around. Some scopes with low-slung mounts and large ocular bells present a problem to those who want to run back-up irons. The LowRider sights are a great option in these situations, especially if you've got a QD scope mount. Occupying just 0.2 inches of space above the rail, these are the lowest profile sights in the bunch. Despite their small size, they do offer windage and elevation adjustments. The adjustments, however, require the use of hex wrenches that look to be about the size of infant syringes on the rear sight and a conformable polymer tube to push down and twist the front. Thankfully, you won't be zeroing these sights more than a few times in their lives. In order to keep things simple, Bobro skipped the dual aperture bracket and chose an aperture size that's somewhere between the near and far peeps on other sights. The forgiving aperture means you won't feel the need to mess with the windage or elevation (and those tiny wrenches) much, if at all.

Daniel Defense Fixed Front/Rear Sight Combo

Weight: 2.86 oz /81 g (set)

Front Height: 1.67 in / 42.5 mm

Front Length: 1 in / 25.5 mm

Rear Height: 1.50 in / 38 mm

Rear Length: 1.38 in / 35 mm

Sight Adjustment:

Front: Elevation; A2 style front post tool

Rear: Dual aperture. Windage; Bullet tip.

Lock: N/A

MSRP: $125

URL: www.danieldefense.com

Daniel Defense BUIS Rear $71.99 brownells.com

411: These aren't technically back-up sights, but full-on irons that can be co-witnessed and used in concert with a 1x red-dot. If the primary goes down, there's no transition time at all. The down side, of course, is living with the lower third of your sight partially obscured. It's doable since optics such as Aimpoints are essentially parallax free, allowing you to look just over the top of the irons and get a solid sight picture. Aside from how quickly they can be brought into service, another big advantage of the 6061-T6 aluminum DD irons is their rock solid stance on the rail. You won't have to worry if the sights are going to pop up and snag something; conversely, once in use, they aren't folding up unless an airplane lands on them. Installing the sights shows you how elegant they are. The crossbolt positions the sight on the rail and acts as it's own recoil lug. There's no mating cleat to loose and the simple design means more machine time for things like glare reducing serrations while still keeping the cost down. We've also found a SureFire X300 mounted just in front of the front sight is a wonderfully ergonomic solution for a 12 o'clock mounted light.

Diamondhead Diamond Integrated Sighting System

Weight: 1.73 oz / 49 g (set)

Front Height: 0.20 in /5.1 mm (stowed)

Front Length: 2.24 in / 56.9 mm (stowed)

Rear Height: 0.20 in / 5.1 mm (stowed)

Rear Length: 2.31 in / 58.8 mm (stowed)

Sight Adjustment:

Front: Elevation; Custom tool.

Rear: Single aperture. Windage; Hex key.

Lock: None

MSRP: $200

URL: www.diamondhead-usa.com

411: We'll admit that the namesake shape of Diamondhead sights felt a little like a gimmick when we first saw them. But, after using the sights for just a few dozen magazines worth of practice, that diamond proved to be a solid feature. Lining the front sight post up through a round aperture alone can leave you feeling like you're throwing a sausage down a bowling lane. Adding corners, posts, and hash marks on the sides of the sights all increase the number of available index points and reduce the time it takes to align the sights on a target. Again, at first we thought the sight looked busy and that all the spikes and angles would be distracting. Not so. We're glad the sights lock when deployed, install with a simple flathead screwdriver, and use a common A2 sight tool for front sight adjustments.

Leitner-Wise Manufacturing Esights

Weight: 0.63 oz / 18 g (set)

Front Height: 0.25 in / 6.4 mm (stowed)

Front Length: 1.36 in / 34.5 mm (stowed)

Rear Height: 0.25 in / 6.3 mm (stowed)

Rear Length: 1.42 in / 36 mm (stowed)

Sight Adjustment:

Front: None

Rear: None

Lock: None

MSRP: $105

URL: www.leitner-wise.com

411: In our opinion, no sight in this roundup hones in so well on the idea of a back-up sight as the billet aluminum eSight. LWM has stripped the BUIS down to the absolute basics, and in doing so relieved us of the, albeit slight, weight penalty for carrying around something we'll likely never use…but feel we must have. These tiny sights weigh barely more than a couple of quarters and are designed to minimize the space they occupy on a rail. They flip up when needed and stay up with a heavy spring-loaded detent, but no lock. There aren't any adjustments at all, so forget about the X ring; it's all center mass with these little guys at anything beyond NFL level passing play distances. The sight arm is stout enough to do its job, but it looks like it won't take much to bend, break, or tear it off the base if it snags.

Magpul MBUS Pro

Magpul MBUS Front $37.99brownells.com

Weight: 3.35 oz / 95 g (set)

Front Height: 0.43 in / 11 mm (stowed)

Front Length: 1.57 in / 40 mm (stowed)

Rear Height: 0.36 in / 9.1 mm (stowed)

Rear Length: 2.08 in / 52.8 mm (stowed)

Sight Adjustment:

Front: Elevation; No tools.

Rear: Dual aperture. Windage; No tools.

Lock: None

MSRP: $190

URL: www.magpul.com

411: Low profile, full featured, and strong as hell. Not an easy combination to pull off in folding iron sights. Magpul did it with the MBUS Pro. Just don't confuse these sights with the original Magpul MBUS sights, though. About the only thing they have in common is the name. There's no polymer here; there isn't even any aluminum. Magpul chose to go with case hardened, Melonite finished steel, leaving no chance these guys will go down when you're already at a deficit with a FUBARed primary optic laying in the dust. As small as these are, they still have a dual aperture and tool-free windage in the rear, and tool-free elevation adjustments up front. We've heard shooters complain about the windage knob, saying it can turn when bumped. We've not seen this happen on our sight, the knob is pretty damned tight. But, YMMV. The thin rear sight tower is a departure from the goal posts we're used to seeing on M4-style sights. The result is a less optically cramped sight picture that improves SA when the sights are in your face. We wish they'd lock, though.

Troy Industries Micro BattleSights – M4 Front and Doa Rear, Tritium

Weight: 1.59 oz / 45 g (set)

Front Height: 0.52 in / 13.3 mm (stowed)

Front Length: 1.79 in / 45.4 mm (stowed)

Rear Height: 0.52 in / 13.3 mm (stowed)

Rear Length: 1.90 in / 48.3 mm (stowed)

Sight Adjustment:

Front: Elevation; A2 front sight post tool

Rear: Dual aperture. Windage; Bullet tip or coin.

Lock: Yes

MSRP: $289

URL: www.troyind.com

411: Choices. Troy's got them. Like bridesmaids at a good wedding, you've got tan, black, average heights, shorties, petites, round ones up front, and of course, some that are lit up like it's last call. We're showing micro (reduced) height sights with Troy's Di-Optic Aperture (DOA) system and tritium inserts here. Of the three heights BattleSights are available in, the Micros are great on high-topped rifles, such as the HK 416, SIG 556, FN SCAR, and others. The Micro's only come in sets and can be ordered with the DOA aperture and M4 (Y) front sight or with round apertures and an HK-style (round) front sight, with or without tritium, and in black or FDE. The Di-Optic system uses a large open diamond for close targets and a smaller diamond with a split point at the top for 300 to 600 yard targets. The larger diamond shape makes for faster sight alignment and target acquisition up close. The smaller diamond's split top leaves a razor thin reference line at the top of the front sight post for enhanced fidelity of long-range targets. If the DOA isn't your thing, check out the conventional setup on the standard height BattleSight below. After all, it's not your wedding.

Troy Industries Folding Battle Sight, HK Front, Standard Rear

Weight: 3.17 oz / 90 g (set)

Front Height: 0.52 in / 13.3 mm (stowed)

Front Length: 2.21 in / 56.2 mm (stowed)

Rear Height: 0.49 in / 12.4 mm (stowed)

Rear Length: 2.13 in / 54.2 mm (stowed)

Sight Adjustment:

Front: Elevation; A2 front sight post tool

Rear: Dual aperture. Windage; Bullet tip or coin.

Lock: Yes, deployed

MSRP: $218

URL: www.troyind.com

411: Troy BattleSights are the folding sights against which all others are compared. Their ramped face is familiar to so many shooters because Troy's are OEM equipment on some of the finest fighting rifles across the industry. The sights are super durable, quick to deploy, and lock up securely; Troy says their stainless steel pin lock system can take 1,000 pounds of force before it gives out. It's good to know that, once deployed, those sights are going to be where you need them no matter how weird things get. Here, we're showing you Troy's standard height BattleSight set with a dual aperture peep rear sight and an HK (round) style front sight. The circle-in-a-circle sight picture that comes with the peep and HK front sight is as fast as it is tried-and-true. The standard height sights can be purchased separately, so M4 front sight base holdouts can grab a rear, rail-mounted sight as a folding option since the BattleSight is the same height as the original AR sights.

Wilson Combat Quick Detach Sight Set, Rail Mount, CSAT Aperture

Weight: 3.46 oz / 98 g (set)

Front Height: 0.43 in / 11 mm (stowed)

Front Length: 2.09 in / 53.2 mm (stowed)

Rear Height: 0.66 in / 16.7 mm (stowed)

Rear Length: 2.20 in / 56 mm (stowed)

Sight Adjustment:

Front: Elevation; A2 front sight post tool

Rear: Dual Aperture with CSAT CQB notch. Windage; No Tools.

Lock: Yes. Locks deployed; spring-loaded release.

MSRP: $240

URL: www.wilsoncombat.com

411: Wilson's QDS sights differentiate themselves from the pack in a couple of ways. First, they feature push-button deployment. Yep, push and the sights rotate into their deployed position under spring tension. Don't worry about accidental deployment, the button takes considerable force to press. The second way these sights stand out is with built-in CSAT rear sight aperture system. The CSAT aperture device is Paul Howe's approach to shooting long and short distances without having to switch the sight aperture on your rear iron sight. Normally, you'll switch from the larger 0.2-inch peep sight for CQB ranges to a smaller, 0.07-inch on the sight for precise work at greater distances. The CSAT adds a notch at the top of the small sight so you can engage distant targets and instantly transition to the close fight by using the top of the aperture like a notched pistol sight. The taller sight aligns the gun and accounts for height-over-bore offset at close distances. No more embarrassing mouth shots when you're aiming at the forehead. Windage adjustment is performed with a finger screw with a hearty detent holding things where you put them.

Zero Bravo REOS (Rapid Engagement Offset Sights)

Weight: 2.08 oz / 59 g (set)

Front Height: N/A

Front Length: 0.39 in / 10 mm

Rear Height: N/A

Rear Length: 0.39 in / 10 mm

Sight Adjustment:

Front: None

Rear: None

Lock: N/A

MSRP: $100

URL: www.zerobravo.com

411: The REOS are fixed sights that clamp to the tube of a magnified optic. They are available in 34mm (shown), 30mm, and 1-inch versions. They are simple. They are efficient. If they were a writer, they'd be Hemingway. Two ounces of 6160 anodized aluminum without a hinge, button, or dial anywhere on 'em. Nothing to snag, break, or otherwise fail. Best part? Since they mount to the scope body, you can use them on a precision rifle that doesn't have a Picatinny rail. There's not a whole lot of adjustment with them. Rotate the rings in relation to each other to pick up a little elevation and windage, but it's a ballpark thing. With such a short sight radius, these aren't 300-yard sights, anyway. But, we were surprised how useful these sights were once we got inside 100 yards. It's harassing fire at 100, but you've got minute-of-bad-guy covered for sure inside 60 yards. The sights line up under a scope's windage knob and present zero chance of snagging on anything. Bonus: REOS can be mounted on either side of the tube; lefties rejoice.

Magpul MBUS Pro Offset Sights

Weight: 3.92 oz / 111 g (set)

Front Height: 0.18 in / 4.5 mm

Front Length: 0.66 in / 16.8 mm

Rear Height: 0.18 in / 4.5 mm

Rear Length: 0.66 in / 16.8 mm

Sight Adjustment: Front: Elevation; No tools.

Rear: Dual aperture. Windage; No tools.

Lock: None

MSRP: $190

URL: www.magpul.com

411: Like their topside brothers, the MBUS Pro Offset sights are tough as balls, and as compact as a scrotum in polar bear swim club outing. They've got all the same features as the inline MBUS. Serrated sight faces, dual rear aperture, toolless windage and elevation adjustment. But, they sit 45 degrees off the barrel, so when the gun is rolled on its side, the sights are over the bore as they would be with a top-mounted sight system. Like a few other offset sights, the MBUS Offsets can crowd the charging handle in an ambidextrous setup. If you have a Raptor, you're going to want to run these guys one or two rail spaces forward for clearance sake. They also ride quite close to the side of the receiver and some brass deflectors may dictate the position the rear sight occupies on the rail, while a few might actually prevent the sights from mounting properly.

Knight's Armament Company 45 Degree Offset Folding Micro Sight Kit, 200-600 Meter, Clamp Mount

Weight: 2.79 oz / 79 g (set)

Front Height: 0.19 in / 4.82 mm

Front Length: 0.70 in / 17.9 mm

Rear Height: 0.19 in / 4.82 mm

Rear Length: 0.70 in / 17.9 mm

Sight Adjustment:

Front: Elevation; No tools.

Rear: Windage, distance; No tools.

Lock: None

MSRP: $281

URL: www.knightarmco.com

411: Knight's Armament Company's line of rear iron sights is split between the basic 300-meter rear leaf and a more capable 200- to 600-meter rotating drum setup. We're looking at the newest version of KAC's 45-degree 200- to 600-meter offsets that feature a beefier clamp mount with a recoil lug in addition to the crossbolt – something we haven't seen on the other sights here. The new mount also makes installation easier than the older model's setscrew-secured arm. KAC says the rotating drum was partly inspired by the flip-up sights found on the FG42 German paratrooper's battle rifle. The rifle combined the utility of a bolt-action rifle, an assault rifle, and a light machinegun – and had a highly adaptable sighting system as a result. The KAC barrel rotates with solid click stops to dial approximate elevation/distance for 200- to 600-meter targets after obtaining either a 25/300 or 50/200 zero. There's also a tool-free windage adjustment that we found too easy to operate. The knob could use a bit more resistance to prevent inadvertent windage adjustments. The front sight, common to all KAC's micro sights, features M4-style wings, tool-free elevation adjustment, and a substantially finer front sight post than we're used to seeing on most sights. The slimmer post increases visual acuity and complements the rear sight's ability to reach out to 600 meters.

Dueck Defense Rapid Transition Sight with Fiber Optics

Weight: 4.69 oz / 133 g (set)

Front Height: 0.20 in / 5 mm

Front Length: 1.00 in / 25.5 mm

Rear Height: 0.20 in / 5 mm

Rear Length: 1.00 in / 25.5 mm

Sight Adjustment:

Front: Elevation; Proprietary FSP tool

Rear: Dual Aperture. Windage, distance; No tools needed.

Lock: N/A

MSRP: $288

URL: www.dueckdefense.com

411: RTS sights are always there and always ready. They can't fold back by accident when shoving the muzzle through a port – a feature that's a result of their three-gun upbringing, but one that anyone can appreciate. Despite their constant, overhanging presence, ours haven't managed to hang up on anything…yet. The sights are made from strong 7075 aluminum and mount with a flathead screwdriver, taking up a few Pic-rail slots. Since the rear doesn't fold, it won't crowd a charging handle. It's also not riding as close as the Magpul and KAC offsets, so it clears a greater range of brass deflectors and can sit further forward, if you need it to. The front sight post is available in standard, fiber optic, and tritium flavors. Combat arms types will appreciate the tritium, three-gunners will gravitate toward the FO version, and budgeteers can get in the door with a solid front sight post. We found the FOs incredibly fast to pick up and worth the risk of the occasional busted rod. You might think otherwise depending on your use. Be warned, adjusting the wider FO and tritium sight posts requires a custom sight tool that's included with the sights.

Troy Industries 45 Degree Offset Folding BattleSight Set

Degree Offset Folding BattleSight Set

Weight: 3.35 oz / 95 g (set)

Front Height: 0.25 in / 6.4 mm

Front Length: 0.59 in / 14.9 mm

Rear Height: 0.25 in / 6.4 mm

Rear Length: 0.59 in / 14.9 mm

Sight Adjustment:

Front: Elevation. Common A2 front sight post tool.

Rear: Dual aperture. Windage; Bullet tip or coin adjustment.

Lock: Yes, deployed

MSRP: $239

URL: www.troyind.com

411: The sight system on Troy's offsets are identical to their non-offset catalogmates. They have the same list of options, but you don't have to worry about lefty or righty concerns since they can mount on either side of the rail. Unscrew the sight from the base, rotate, and screw it back in. Pretty handy for wrong-eyed shooters. Modularity comes with a cost, though. The offset BattleSights are larger than the purpose-built offsets. Consequently, you're hemmed in on the mounting position. The brass deflector on our forged Armalite and billet Mega Arms uppers limited the forward placement of the rear sight. Not a problem with standard charging handles. But, again, a no-go with something like a Raptor. We couldn't fold the rear sight since the handle was in the way. All we can say is, if you're running anything other than Mil-spec, try mounting these before you buy a set. Once you know they fit, you can bet these offset BattleSights are emmeffer strong, accurate, and dependable.

XS Sighting Systems CSAT Aperture for M4 and Troy sights

MSRP: $35 to $40

URL: www.xssights.com

411: If you like the CSAT aperture on the Wilson Combat QD sights above, but lack the need for new sights, you have options. XS Sights makes the CSAT aperture available as a user installable insert for standard AR-15/M16/M4 rear sights and Troy BattleSights. Installation is straightforward and requires a screwdriver, good close vision, and 20 minutes of being left-the-hell-alone.