The HK SL8 carbine is a unique firearm in many respects. The rifle fires the .223 Remington or 5.56x45mm NATO cartridge and feeds from a 10, 20 or 30 round detachable magazine. The SL8 was originally developed for the German Bundeswehr, to provide a weapon for training reservists similar to the G36 and able to be provided to reserve organizations not able to provide military grade armaments.
When I got the rifle home from the gun store, I unpacked it from the box and familiarized myself with it. The SL-8 comes with quite a bit of accessories including; three magazines, a gun lock, a multi tool, a three point HK sling, manual, sticker, and in my case a RADDLOCK instead of a magazine release lever. I live in California, and through a legal quirk of the California “Assault Weapon” laws, SL-8 rifles are legal to own, provided they have a
mechanism installed that requires the use of a tool to remove the magazine from the rifle. The mechanism is called the RADDLOCK, and a quick Internet search will provide the readers with more information, if they are so inclined.
A cursory inspection of the SL-8′s fit and finish reveals clean welds, even coloring of the plastic, and excellent assembly and attention to detail as is to be expected from HK products. The multi tool and the gun lock are absolute junk, I can’t understand why HK would want their logo printed on these poor quality products. The magazines are single stack, have a ten round capacity, and have only one magazine lip. Although the apparent quality of the magazines is good, they are difficult to load, as the loaded round has to be depressed into the magazine to load the next round. Think of loading a pistol magazine and you will have a good idea of what this is like. The magazines feed ammunition into the rifle smoothly and positively lock into the magazine well. The magazine design is the first indication that the SL-8 is a quirky rifle.
Taking apart the SL-8 requires tools and a secure place to put all of the parts. Taking the rifle apart reminds the operator that this is a sporting arm rather than a combat weapon. There are three separate fastening systems that hold the rifle together; the first is two allen cap screws that hold the receiver and stock assembly, the second is a spring locking push pin that holds the trigger group/stock to the magazine well and receiver, and the last is a loop sling attachment/threaded pin and nut that hold the fore end to the receiver. I cannot fathom why HK decided to do this from an engineering standpoint (I am a Mechanical Engineer so I feel comfortable critiquing HK in this way) or a manufacturing one; it simply makes no sense and increases the cost of the rifle to build it this way. Once the three “fastener systems” are removed, the rifle’s butt stock/trigger group can be removed, along with the recoil spring. The fore end slides off of the front of the rifle, exposing the gas piston. The bolt carrier assembly can be slid out of the back of the rifle, the magazine well can be swung out of the way, and the gas piston assembly can be depressed and swung off to the left or right of the barrel – allowing the piston itself to drop out. The bolt group is reminiscent of an AR-15, with a stoner-derived bolt, a firing pin, firing pin key, bolt key, extractor and ejector being very similar to the American design. A sharp eye will notice that one of the locking lugs on the bolt has been ground down, which makes it impossible for the SL-8 bolt to load a round from a double-stack magazine. Once the SL-8 was “field stripped” (I use that term loosely because I do not recommend taking this rifle apart in the field, there are just too many parts to lose), a close inspection revealed that the barrel rifling, barrel crown, and the bolt recess in the bolt carrier were all bare steel. The outside of all of these parts were coated in HK’s manganese-phosphate parkerizing, but the insides were bare steel. The operator must take special care to ensure these parts are well oiled so they do not rust. Again, the SL-8 is a sporting arm, but I cannot understand why HK would make this rifle so vulnerable to corrosion. Once, I have actually had the bolt carrier internals develop a light rust – I now keep the entire rifle drenched in oil until it is time for a range trip.
Would I buy this rifle again? The answer is Yes…I like the way this gun shoots….I like the accuracy, and I like the smoothness
There is no way around this point. The ergonomics of the SL-8 are absolutely terrible. The length of pull is acceptable, but the thumb hole stock is set up all wrong. The hole is too low to thread your thumb through to operate the safety, and the trigger is too far back. I have fired a real G-36k, and the pistol grip and stock setup are fantastic; it is too bad that HK decided to design the SL-8 stock the way they did. If the shooter has small hands and a diminutive body, the thumb hole stock might be comfortable; but being a corn-fed 6′-4″ boy from Texas, I don’t fit into that category. The SL-8 stock has an adjustable length of pull and comb height, but both require the use of inserts that you need to buy from HK to make them work. The rifle comes with one each, one for the comb, and one for the butt plate. The rifle also has a picatinny rail installed on the top for scope use, but unless your head is as big as Andre the Giant’s, the rail is way too high to use normal optics with only one comb riser – which brings us to another point, if you install another comb riser, the screws that hold the cheek piece on won’t fit anymore, they are too short. The best way out of this problem is to install a new scope rail that is lower (they are easy to find). Once that is done, the rifle is much more comfortable to shoot. To be fair, once the stock adjustments are sorted out, I like the fact that the length of pull and cheek piece can be locked down tight and that they won’t move under any circumstances. The rifle is best shot off of a bench, or employing one of the classic shooting positions. In stock form, I wouldn’t attend a carbine class with the SL-8, because the ergonomics of the rifle would drive me crazy after an hour or so of drills. As far as a DMR/SPR/Precision Rifle class, I think you are good to go if you can live with the thumb hole stock.
This is a limited area. For the most part, you are pretty much stuck with HK parts for the G-36, and most of these parts are very expensive. Although it is true that there are some American made parts, these are for 922r compliance, or to make the SL-8 accept standard capacity magazines, pistol grips, and folding butt stocks. As shipped, the SL-8 has been designed to make it very difficult to accept any “assault rifle” features; I don’t blame HK for this, because they had to do these things so ATF would allow the rifle to be sold in the US (and the rules ATF uses to clear a rifle for sale are not uniform and apply to different manufacturers differently, sometimes unfairly). The SL-8 has very few options when it comes to a rail fore end, Knight’s armament company made one (once upon a time, they are rare & expensive today), and Brugger & Thommet makes another. Actually, you are better off buying the rail sections that HK (and others) make for the SL-8 that bolt onto the factory fore ends. Some might question the wisdom of buying a gun and then having to buy additional parts to make a $2,000 rifle work for the operator, but ask yourself honestly; do any of us own a stock AR-15? I don’t, and neither does anyone I know.
Accuracy and Shooting Impressions:
When I took the SL8 rifle to the range, I did a quick zero at 50 yards to get on paper, then moved the target back to 100 yards to see what groups I could get with the rifle. The wind was calm, elevation was 150 feet, and the temperature was 68F. I used a Nightforce 5.5-18 x 50mm scope for the accuracy and function tests. I started out with Winchester 55 grain XM193. Grouping was around 4″, but that was to be expected with a 1:7 twist barrel,
intended to stabilize heavier bullets. After the expected results with the XM193, I moved on to what I thought the rifle really wanted anyway, some 62 grain Federal XM855. The grouping was just under 1.75″ for a four round group. Think about that for a minute; This rifle just shot a little over minute of angle with Military 5.56 ammunition (in fact, another shooter and I have been able to get a few two or three shot groups that were under 1″, but we were not consistent in our accuracy due to the ergonomics getting in the way of a proper shooting position). There is no doubt whatsoever in my mind that the SL-8 can get under one MOA with the proper hand loads, or match ammunition. However, what I was most impressed with was the recoil impulse. The rifle shoots smooth and doesn’t spit grease in my face like my D.I. AR-15 is prone to do. The rifle works flawlessly with every type of ammunition I have tried, the SL-8 eats everything! I have never had a jam from the magazines or with any ammunition I have tried. The bolt holds open each and every time the rifle exhausts its supply of ammunition, and the recoil was as light if not lighter than any other 5.56 rifle I have shot. The trigger pull on my particular rifle broke clean, and although the break was far from a match trigger, there was little if any creep. At the end of the day, the SL-8 is a joy to shoot, and is very accurate.
Converting the SL-8 to look like a G-36:
Let’s be honest, many people look at the SL-8 and think, “That rifle is basically a G-36…I wonder if?”. In a nut shell, if you want the SL-8 to look like a G-36, it can be done, but this process involves tools like milling machines and lots of spare parts. A full SL-8 to G-36 conversion that would fool a HK armorer at a glance would cost well over $4,000 all in, with the rifle, parts, and gunsmithing. I won’t get into the nuances of how to do this conversion in this article, but interested readers can go to HKPRO.com to search for threads that deal with this topic. A question I get a lot is, “Do you intend to convert your SL-8 to a G-36 configuration?”. The answer is yes, but I will be doing a lot of the work myself over a multi-year period, and I will be purchasing a milling machine and lathe as part of the conversion. This leads to the question, “Why would anyone want to purchase this rifle?”. The answer is, the SL-8 is a rifle that suits a few types of users well;
- First, those who like to tinker, bought the SL8 specifically to convert it so it looks like a G-36, and approach the problems that a SL-8 to G-36 conversion presents as a challenge and a great deal of fun. The challenge is significant, it involves the manufacture or purchase of special tools, the use of a lathe and milling machine, and the ability to fuse and weld plastic – with the consequence that if a mistake is made, you have a $2,000 paperweight. This conversion project is not for the feint of heart, but there are gun smiths out there (Dakota Tactical and Tom Bostic) that will perform this work for you (labor only, no parts).
- Second, those who bought the rifle for its inherent accuracy and for shooting at longer ranges. The rifle has no problems “ringing steel” at 500 yards, especially with heavier bullets. As a hunting rifle, it is good for ground squirrels or coyotes, but the ten round magazine might be an issue in some states for hunting.
- Third, those who want to purchase the HK rifle for collector reasons, as HK has discontinued the SL-8 (however it is still available on the open market).
Would I buy the HK SL8 again? The answer is Yes. I like the way this gun shoots once the ergonomic issues have been remedied. I like the accuracy, and I like the smoothness of the way this gun cycles. Another reason I like the rifle is that it immediately draws stares and drooling from other people at the firing range – these rifles are very rare here in California, I have never seen one in the “wild” before I bought mine. For now, I intend to use the rifle for precision shooting at the 300 – 500 yard range, and I have been extremely happy with my purchase.