The SL8; HK's New Grey Sporter


Magazine System

In compliance with recently-imposed federal restrictions on the importation of rifles that will accept available high capacity magazines, HK was forced to modify the G36's existing magazine system. That they would have to do so was evident to many who anxiously awaited the SL8's availability here in the U.S. What was uncertain was the extent of the modification. SL8s that are sold outside of the U.S. simply employ a 10 round, staggered, cropped G36 magazine, and this would seem to comply with U.S. laws considering the fact that there were no G36 magazines here in the states prior to September 1994. NATO magazine wells or G36 C-Mag towers would have remedied the capacity problem under this most ideal scenario. It has unfortunately ended that U.S.-bound SL8s are not as modular as the G36 in this respect.

The SL8's magazine system differs from that of the G36 in three ways. First, its transparent, smoke grey magazine has a maximum capacity of 10 rounds which are stacked rather than staggered. This design prohibits loading from any type of stripper clip, and rounds must be loaded individually as with a Colt 1911 magazine, for example. Secondly, the detachable magazine well is beveled on the right side to accomodate this narrow magazine. This offsets the magazine slightly leftward, and all rounds consequently feed over the left ramp in the barrel extension. The magazine well hinges from the front on studs in the receiver and is secured at the rear by the same push pin that helps to hold the stock/grip/fire-control assembly in place. Finally, the receiver is modified just above the magazine well with a matching bevel that is narrow enough to preclude the insertion of, say, an M16 magazine. Damn.

The magazine will accept all 10 rounds without any loading difficulties, and it feeds flawlessly as long as the ammo is loaded in the right direction. To assist the dullards out there, HK felt compelled to mold a picture of a cartridge into the side of the magazine indicating the proper Schußrichtung. Spare mags are available with a suggested retail price of $42.

The wide, serrated, polymer magazine release is located aft of the magazine well and, like the flapper release commonly retrofitted to older HK rifles and submachine guns, it allows for single-handed magazine changes.

When the last shot is fired or when the SL8's cocking handle is retracted with an empty magazine in place, the magazine's follower engages a bolt catch that is integral to the fire control housing. It can also be engaged in the absence of a magazine by retracting the cocking handle and pressing a button inside the top, front portion of the trigger area. This button, by the way, is actually the polymer-coated base of the bolt catch. The bolt can only be released by slightly retracting the cocking handle in the absence loading is not advise. In the rifle's standard configuration, access to the ambidextrous cocking handle is somewhat restricted by a low-lying, one-piece sight rail. This rail features two slight cutouts - one for when the bolt is in battery and one for when it is retracted - that allow just enough room for the user to grasp the cocking handle with a finger and pivot it outwards. HK markets several other devices that replace this rail, and they all happen to allow greater access to the cocking handle.

Sighting Provisions

The SL8's Weaver-type scope/sight rail, which is approximately 20 3/4 inches in length, extends to the forward edge of the handguard. It will accept virtually any type of optics, though the SL8 is shipped with a set of iron (actually polymer) sights that offer a maximum 18-inch sight radius. The zypher-profiled front sight is contoured to match the rearward slope of the rail which in turn is contoured to match the rearward slope of the handguard. The rail readily accepts Leupold Mk IV rings, A.R.M.S. #22 throw-lever rings, A.R.M.S. #19 throw-lever mounts, etc., so users should have no difficutlies in outfitting their SL8s with choice optics.

As an accessory, HK intends to offer an abbreviated, 13-inch picitinny rail - part of a broader lineup of sighting arrangements that interchange between the G36 and SL8. This rail does not extend beyond its front mounting point, so it only offers a 10-inch sight radius when using the factory-supplied sights. Its merits are: 1) the rail, like any proper picitinny rail, is jam packed with enough grooves to satisfy any mount fiend and 2) it allows improved access to the SL8's cocking handle.

For maximum cocking handle access with the added benefit of integral optics, buy one of the G36 carry handles. These mount perfectly on an SL8 in lieu of its sight rail and are available with a 1.5x scope, a 3.5x scope or a dual 3.5x scope/red dot sight arrangement. These scopes all share the same reticle pattern which features lead marks, rangefinding gradiants and drop-compensated aiming points. Windage and elevation adjustments are made using the supplied HK tool's 2.5mm allen wrench, with each click shifting the bullet's point of impact by 1.0 inch at 100 meters. The Hensoldt-made red dot sight is illuminated by both batteries and fiber optics. From the rear, it is shaped roughly like a club (as in the card suit) with the reticle on top, the on/off switch on the lower left and the battery compartment on the lower right. A hood on top of the unit slides forward to reveal a fiber optic plate that collects ambient light to illuminate the dot.

While this red dot sight works as designed and is probably robust enough for the military and law enforcement applications for which it was conceived, it still does not make the best use of existing optical technology. Had someone like Trijicon been tasked with making this, they would have charged the standard scope's reticle with tritium and dispensed with the battery-powered red dot sight altogether, producing a more streamlined, versatile, ready and reliable combat sight. Hensoldt sometimes employs tritium in scopes that they refer to as "beta lighted", but they use it so sparingly that after a decade it takes a Geiger counter to detect it at all. In Hensoldt's defense though, the German federal authorities are strict on the use of tritium, and customs officials tend to frown upon anything that is marked with that little radioactive symbol.

When the red dot is just not enough and when you have more money than you know what to do with, you can always buy Hensoldt's NSA 80 II passive night vision device. This $8,000 jewel locks onto the G36 carry handle and projects its view of the target through the regular optics via a periscope that thrusts downward through a port in the carry handle. If the unlikely opportunity to test one of these ever presents itself, I will seize it and tell you all about the unit's pros and cons.

Returning briefly to the sights that HK ships with every SL8, prepare for disappointment. The fixed front sight sports a rather course blade for target use (though so does SIG's quite-accurate 550). At least the front sight is shielded which is more than can be said for the rear sight. This L-type flip unit has 100 and 300 meter aperatures, either of which stand exposed and ready for damage during use or transit. The sight itself rests on a spring-loaded platform that hinges on a roll pin at the rear of the polymer sight housing. Elevation adjustments are made by turning an allen-head screw in the center of the platform, thereby raising or lowering the ceiling of its spring-powered arc. Windage adjustments are made by inserting the same 2mm hex wrench through a small port in the sight housing and turning a screw that runs in standard fashion through the flip sight's axis. This spartan sight affair is functional enough not to inhibit accurate shooting, but my experience with it has generated a newfound appreciation for the AR-15's superior E2 sight assembly.

Target Adaptations

The SL8 is ostensibly a target rifle, and consumers could therefore reasonably expect HK to have refined certain aspects of the G36 to lend the sporter some advantages over its military counterpart with respect to precision shooting. For its purpose, the SL8 does boast three advantages over the G36: a match-grade barrel, a fully-adjustable stock and a lightened trigger pull - features that cost hundreds of additional dollars when HK offers them as accessories for their other civilian and military rifles.

Its 20.80-inch long, match-contoured barrel slightly tapers from ~0.835 inches at the chamber to ~0.785 inches at the muzzle with no step down beyond its roll-pinned gas block - a heavier barrel contour than that of the MG36, the light machine gun variant of the G36. The cold hammer forged barrel is conventionally-rifled with a right-hand twist of one turn in seven inches which implies that it will achieve optimum accuracy with heavier bullets such as Sierra's 69gr HPBT and suitable accuracy with 62gr SS109. The SL8's gas-operated mechanism obviates the need for the internal chamber flutes that are present in the rifles and submachine guns patterened after HK's recoil-operated G3. However, its chamber is fluted externally for increased heat dissipation, a retention of the measure employed on G36 barrels to reduce the liklihood of cook-offs during sustained full-auto fire.

The barrel extension is molded into the receiver, and the barrel is secured to it by means of a cylindrical nut that is slotted at 90° angles. Barrel changes are effected through the use of the very same tool that is issued to Bundeswehr unit armorers for that purpose. It should go without saying that this newest system from HK employing a barrel nut that is torqued to ~50 ft. lbs. is logistically superior to G3-patterened systems, the barrels of which are pinned to the trunion after their installation by a 10-ton press. Also, the barrel is free-floated in the sense that it does not touch the the one-piece, polymer forend which is secured to the receiver by a push pin.

The forend is a simple affair: it does not have any lateral bipod grooves or vent holes, so it rests comfortably across the palm. It features a molded sling attachment point on the bottom at the front. Just aft of this are two molded-in, threaded steel studs that are spaced 3.5 inches apart and are intended for attaching the very same picitinny accessory rail that HK markets for use with their UMP45. Knight's Armament Company (KAC) sells a Harris bipod adaptor for their Modular Weapon System (MWS) which should work well in conjunction with this simple rail.

For those who do not mind a motley rifle, HK also sells their black, vented G36 forend. This readily accepts the polymer G36 bipod which mates to it by removing the front sling pin, sliding the bipod over a lip at its front edge and reinserting the sling pin through two holes in the bipod's fulcrum. The sling pin is held under tension by a flat spring that is accessible on the bottom of the forend.

If the idea of an SL8 bristling with lights, lasers and CQB wall feelers appeals to you, then go all out and acquire the KAC G36 MWS. This forend features picitinny rails on all four sides and offers greater heat dissipation than the SL8 or G36 forends made by HK which lack any type of heat shields.

The standard forend, like the sight rail and gas piston assembly, is relatively lightweight, but the barrel is the SL8's single heaviest component. Thus, the rifle is noticeably front heavy. Shooters should nonetheless find the SL8 comfortable to shoulder and fire, and this is due largely to the excellent ergonomics of the rifle's stock.

The rear stock assembly is fully adjustable and includes the grip and fire control mechanism. The buttplate slides in and out of the hollow stock unit and is secured by two allen head screws that are inserted through opposite sides of the stock and tightend into any one of the buttplate's six threaded, steel studs. Adjustments can be made within a range of 1 5/8" and require the use of the tool set's 5mm allen wrench. The SL8 is shipped with one stock spacer which indexes the buttplate to the second stud. HK sells extra stock spacers for $6.00 each. A rubber butt pad and a polymer sling attachment point are molded into this sliding assembly.

Two flush-fitting, threaded, steel inserts are molded into the top of the stock and serve as mounting points for a cheekpiece and, as necessary, a series of stackable spacers. The cheekpiece and one spacer are supplied with the rifle and provide a proper cheek weld when using the factory sights. Extra spacers are available from HK for $7.00 each and might be useful if, say, a scope with a large objective bell were mounted on the rail using high rings. The stock is perfectly comfortable with no cheekpiece - a necessary arrangement when the rifle is outfitted with the G36 carry handle and integral optics.

While the butt and cheek portions of the stock can be adjusted to suit most shooters, the thumbhole is intended to be a one-size-fits-all/one-shape-fits-the-rules arrangement. HK crafted a fairly comfortable grip considering the confines of ridiculous federal regulations that they had to work within. Unlike many thumbhole stocks on the market, this one is symmetrically-shaped to accomodate both left- and right-handed shooters. However, it does make operating the ambidextrous selector lever difficult.

What finally distinguishes the SL8 from the G36 from a target shooting perspective is its redesigned trigger mechanism. This dispenses with the G36's AUG-style auto sear - generally a useful component - but features an additional "locking lever", the purpose of which eludes me. What matters is that the trigger breaks crisply at about 3 1/2 lbs.

The entire stock assembly is fastened to the receiver using two allen head screws at the rear and a push pin just behind the magazine well. The screws are inserted through steel reinforced holes in the receiver and tightened into a single threaded stud that is molded into the stock. They must be loosened in order to remove the bolt carrier assembly for cleaning; a push pin would have been more convenient.

Receiver Internals

Internally, the SL8 is virtually identical to the G36, the only difference being that the SL8's bolt carrier lacks the lugs that would trip the G36's auto sear. The carrier design, like the rifle's general method of operation, is borrowed directly from the AR-18. It houses a Stoner-style rotating bolt, cam piece, firing pin and firing pin retaining pin.

The chrome-plated bolt is machined with six locking lugs, while the extractor is machined with a contoured lug that performs no locking function at all. Each lug is thicker than its counterpart on an M16 or AUG bolt, either of which sport seven machined lugs, so the SL8's bolt is theoretically more robust. The extractor pivots on a pin that protrudes slightly from both sides of the bolt. It takes a hammer and a punch to remove this stubborn little pin, and HK actually machined two slots into the front surface of the carrier to accomodate it. The extractor spring assembly consists of the spring and bushing that are typical amongst Stoner bolts. Anyone concerned with extraction problems might consider obtaining and installing an Armforte D-Fender which is designed to increase extraction force fourfold in this type of bolt system. As with the AUG bolt, the ejector and ejector spring are inserted through the a hole in the rear of the bolt and are contained by a roll pin. The bolt is held into the carrier by the cam pin.

The cam pin is inserted along its slotted path in the left side of the carrier and is retained by the springless firing pin. The firing pin is in turn captured by its own retaining pin that is inserted through the left side of the carrier and held under tension by a high-temperature rubber o-ring.

The recoil spring assembly, which is situated directly above the bolt, is roughly 8-inches long and slides into its own hole in the carrier from the rear. It consists of a chrome-plated tube with a spring around it and a polymer bushing at the front end. The spring and bushing are secured by chrome-plated caps that are crimped to both ends of tube. When the bolt carrier is retracted, it compresses the spring between the bushing and the rear cap, leaving the front portion of the spring tube visable through a port in the top of the receiver that is ordinarly obscured by the bolt extension and the charging handle. A rubber buffer that snaps into the stock's backplate absorbs bolt's remaining momentum.

Receiver Externals

The bolt's recoil impulse is transmitted from the gas piston via a spring-loaded piston rod that is about 8 1/2 inches long. During the firing cycle, gas is vented upwards into the gas block through a port in the barrel. Some of it is bled off into the atmosphere through a tiny port in the front of the gas block, while the rest forces the gas piston violently rearward against the piston rod, delivering all of the energy necessary to cycle the action.

The carbon that would ordinarily foul the components inside of an M16 receiver simply bakes onto the SL8's gas piston which is chrome-plated for ease of cleaning. Like the gas piston in an AR-18 or AUG, it is fitted with three split gas rings which must be disaligned to generate enough resistance to the gas flow to ensure proper functioning. This is without a doubt the SL8's highest-maintenance component, and it should be cleaned, not with a lubricant like BreakFree, but with a polish like Brasso or Flitz. Of course, HK claims that the SL8 can handle 15,000 rounds between cleaning sessions, and their claim seems indirectly vindicated by encounters that I have had with AUG owners who shot their rifles for years without knowing how to even remove their gas pistons. What is certain is that this system keeps the receiver's internals relatively clean and carbon-free. It is itself completely shrouded by the forend.

The action's cleanliness, coupled with its unusually smooth operation, seems to have obviated the need for any type of forward-assist mechanism, though one is subtly present. To utilize it, simply pivot the cocking handle 90° in either direction and push it inwards. It will lock into this position and provide a 1.5-inch wide bearing surface that can be pushed forward gently or pounded on depending on whether you want to overcome or compound whatever problem that initially prompted failure. The receiver also features a molded-in case deflector for left-handed firing, and this sends ejected casings almost directly rightwards without damaging them. Finally - a reloader-friendly HK rifle that neither dents nor striates spent cartridges!

Other Standard Accessories

As already noted, each SL8 is shipped with its own tool kit, this in a red, Swiss-Army-type arrangement featuring 2, 2.5, 3, 4, 5 and 8mm hex wrenches as well as phillips and flat head scewdrivers. The 2mm hex wrench is used to adjust the fixed sights, the 2.5mm hex wrench is used to adjust carry handle optics, the 5mm hex wrench is used to adjust or remove the stock, the phillips head screwdriver is used remove the sights, sight rail or carry handle and the remaining four tools are a bonus. HK obviously bought someone else's tool kit and applied their own logo, but that is fine. They deserve an ovation for supplying this necessary item with the rifle rather than charging extra for it - their standard operating procedure.

The SL8 is also shipped with a black, nylon sling that someone might actually use for a change. Most HK rifle owners whom I ever met may have owned the older green canvas or brown leather factory slings as accessories, but they rarely used them because they either could not decipher them or were reluctant to allow the steel hardware to scratch their pretty (and expensive) rifles. This new sling is not problematic in either sense: its familiar steel QD snaps attach to polymer sling points where they can not really inflict much cosmetic damage, and it is simple to operate. It allows the rifle to be carried close to the chest in a ready mode and is extended by releasing its fastex buckle. Those who appreciate the finer things in life should be pleased to hear that it sports a genuine ITW Nexus buckle rather than some cheap, Chinese-pirated clone.

Rounding off the accessory list with a sign of the times, HK ships every SL8 with its own gun lock. This is essentially a padlock with a long, rubber-coated wire designed to keep the bolt out of battery and prevent the insertion of a magazine. It may safely confine a child's natural curiousity, but a lock is not the ideal tool for dealing with people who are emotionally imbalanced, dangerously stupid or outright criminal.

Overall Impression

The SL8 is basically well-executed considering the guidelines foisted upon HK by current, obtuse U.S. regulations. Ironically, HK resolved the stock, barrel, trigger mechanism and magazine issues in ways that improved the system's target capabilities, while they fumbled on the fixed sight design - an aspect over which they had complete discretion. This is of little concern though, as the rifle is probably better off with a scope anyway. When testing one specimen that was outfitted with a Leupold Mk IV M3, I found that I could hit 1-inch squares at 100 yards on demand which implies that the SL8 will perform as designed.

The SL8 carries a suggested retail price of $1,599 - an arguable bargain when you compare its features and functionality to those of other grey sporters like Steyr's overrated Scout rifle. It incorporates HK's most current materials and design technology and is every bit as rugged and reliable as its military counterpart. Still, there is one conceptual problem surrounding the SL8 that should not be overlooked: other entities are using your tax dollars to equip themselves with the real deal while simultaneously dictating to you that the SL8 is all that you can own - for now.

SL8 Technical Specifications
Caliber 5.56x45mm
Operating System Gas-operated, rotating bolt
Rifling Right-hand twist of 1 turn in 7 inches
Feed Mechanism 10rd box magazine
Weight 8.60 pounds (3.90 kg)
Barrel length 20.80 inches (528mm)
Overall length 38.58 inches (980mm)
Width 2.36 inches (60mm)
Height 9.84 inches (250mm)