Zion-15 SPR 18 — IWI’s No-Nonsense AR-15

The “SPR” in IWI’s Zion-15 SPR 18 stands for Special Purpose Rifle. SPR is a 21^st century military acronym born from the M4 carbine’s service wide displacement of the traditional, 20 inch barrel M16 rifle. The M4s do a lot of things well, but, with a 14.5 inch barrel, long range accuracy will never be its strong suit. A weapon with equal firepower and greater long range accuracy was needed within regular infantry fireteams to span the gap between the M4’s maximum effective range of 300 meters and sniper rifles minimum range of 600 meters. That something was the Designated Marksman Rifle (DMR).

The U.S. Navy’s Mk12 SPR, which the IWI SPR 18 is modeled after, was designed for the DMR role in United States Special Operation Forces (SOF) units. In service from 2002 to 2017, it also saw combat with USMC infantry designated marksmen (DM) in Iraq and Afghanistan where the need to engage targets beyond 300 yards proved more common than anticipated.

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To take full advantage of its superior accuracy, the Mk12 had special ammunition and was generally equipped with a bipod and optics having greater magnification than those used standard issue M4s. Black Hills Ammunition developed the Mk 262 Special Ball LR (Long Range) for the SPR using a 77 grain Sierra Match King OTM (Open Tip Match) boat tail bullet to maximize its long range performance.

IWI Zion-15 SPR 18 — Military Inspired

The IWI SPR 18 is not a military rifle clone. It’s more a military inspired competition rifle. It has the 18 inch, free floated, SOCOM profile heavy barrel with 1 in 8 inch twist rifling that was the heart of the Mk12 SPR. IWI used a 4150 chrome moly vanadium alloy barrel steel and nitride treated it for rust and wear resistance. Since the muzzle is threaded ½-28 and fitted with the standard military A2 flash hider it’s also suppressor ready. 

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In keeping with the spirit of enhanced accuracy, the SPR 18 has the IWI Precision Match Trigger. This cassette type, two stage, trigger features a flat trigger face for more consistent control and a 3 pound pull weight. The approximately 0.07 inch overall pull length is remarkably short. It’s split about evenly between the first stage take-up and pressing through the wall to a crisp break. I could detect no overtravel.

Military Grade, American Made

IWI uses forgings for their upper and lower receivers. Upper to lower fit was good, what minimal wiggle there was easily taken up by tightening the nylon tipped tension screw underneath the pistol grip. The gas key on the nitride treated bolt carrier group is staked down, as is the buffer tube castle nut to insure they stay in place. 

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The SPR 18 has tough, military grade and American made, B5 Systems stock furniture. B5 Systems made SOPMOD stocks for our Special Forces. Their Enhanced SOPMOD five position buttstock has two fixed sling slots, one-piece anti-rotation QD sling mounts, a no-slip cushioned buttpad, a sure grip stock latch, and dual water resistant storage compartments. It provides a great check-weld surface and length of pull adjustment to adapt to body armor and scope eye relief requirements. The13 degree grip angle of their beavertail Type 23 P pistol grip is ten degrees steeper than the standard M16A2 pistol grip, larger in circumference, and aggressively textured like 80 grit sandpaper. It fills the hand more fully than the traditional grip, especially at the top, but the design intent was to improve ergonomics and ensure proper trigger finger indexing. Personally, I think this grip feels more natural, regardless of the shooting position. 

Accuracy Advantages

Beyond high build quality, and the inherent accuracy advantages of a great trigger and a rigid heavy 18-inch barrel, the standout feature of the SPR 18 that should grab the attention of competition shooters is the 15 inches of integral Swiss ARCA rail on the bottom of the IWI 17-inch octagonal free-floated aluminum handguard. The top of handguard is entirely Picatinny rail, but the bottom is all wide, flat, ARCA rail except for the two inches next to the receiver. All seven lower sides have M-LOK slots for your accessories.

The ARCA rail system is like a wider Picatinny rail without the slots. In addition to maximum versatility in positioning accessories along its length, it allows for faster repositioning of accessories because they can be simply loosened and slid forward or backward to the desired spot. By contrast, a slotted Picatinny rail is designed to keep accessories where you put them, and even with quick release levers you still need to dismount them entirely to change their position. 

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Competition shooters like the ARCA rail because they can easily shift the location of their bipods or rail mounted shooting bags on the move during matches and also lock onto optics tripods. The ARCA system was originally developed for securely mounting camera equipment and offered good weight distribution, a secure hold, and speed of use. I don’ t see it replacing the Picatinny rail on the battlefield, but it has great merit for sporting and law enforcement purposes.

During testing, I fired the SPR 18 from the bench using a B&T Industries LLC Atlas BT46-LW17 PSR bipod, so named because it was selected by United States Special Operations Command (USSOCOM) for their Precision Sniper Rifle (PSR) weapon system. It is virtually indestructible, compact and lightweight and allows 30 degrees of pan and cant making it easier to track moving targets and adjust your aim without picking up and shifting the bipod. The legs are independently adjustable with five length positions from 5.2 to 9.6 inches and can be set at 0, 45, 90, 135 and 180 degrees. The latter feature is very helpful when you need the muzzle closer to the ground, or the bench in my case. 

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 ARCA rail is just starting to catch on in America and clamps are available for B&T Industries Atlas bipods through their website www.Accu-Shot.com. I didn’t have one so I mounted it to forward M-LOK slots on the bottom of the ARCA rail using a BT80 M-LOK Flush Cup Rail section. Since this also includes a QD sling swivel socket, I killed two birds with one stone.

Shooting Impressions

I tested the SPR-18 at 100 yards, shooting five shot strings with the aid of an 8x scope and got flawless reliability with all ammo types tested. As you might expect, the rifle shot best with heavier bullets. Federal Premium .23 Rem 69 grain Match King Gold Medal Match averaged groups measuring 1.18 inches and military issue Mk 262 MOD 1-C 77 grain Special Ball LR, the stuff made by Black Hills Ammunition, shot groups averaging 1.2 inches. What surprised me was that Hornady American Gunner 55 grain JHP shot average groups of 1.35 inches. Who doesn’t like a surprise like that?

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Specification: IWI Zion-15 SPR 18