Keeping it kurz
Modding and shooting the Heckler & Koch SP5K
It only takes a split second to recognize the iconic lines of the MP5. One quick glimpse and you already know what it is. That’s how famous this gun is. Introduced in 1964, Heckler & Koch’s MP5 “machinepistole,” or submachine gun, is among the most famous modern-era firearms.
The MP5 has been a workhorse for special operations and other military and law enforcement units worldwide for more than 50 years. To put that in perspective, the year that the MP5 was introduced saw LBJ in the Oval Office and the Beatles make their first appearance on the Ed Sullivan Show. Since then, its variants have been seen action in all types of scenarios. It’s even been featured on the big (and little) screen for decades. As popular as the firearm is, it’s hard to believe that a variant hasn’t been available to the civilian market in the States for over two decades.
With more than half a million MP5S and variants sold worldwide, it boggles the mind why “the rest of us” were left without an official HK model until 2016. In 1989, HK released a pistol version of the MP5 called the SP89. It was basically a semi-auto version of the MP5K, which is
“Designed as a pistol, the SP5K is meant to recall the look and feel of the original mp5k.”
a pistol version of the MP5. The MP5K is a shortened MP5, with the K standing for Kurz—or “short” in German. It was originally developed for use in confined spaces and is suited for personal defense and other sometimes-clandestine operations.
MP5K & SP89
The civilian version SP89 was imported for only four short years and was made unavailable for civilian purchase due to the 1994 Crime Bill. From then on, HK fans everywhere were forced to buy their SP89 or MP5 variant on the secondary market or buy a clone. Count yourself lucky if you picked one up back then. For the rest of us, we would have to wait another twenty-plus years for our next chance to get our hands on one.
Unlike other MP5S, the MP5K and SP89 do not have shoulder stocks and have end caps covering the back of the receiver. The bolts and receivers were shortened at the rear as well, making them remarkably short. The same goes with the SP5K. It is essentially a modernized version of the SP89 as both are semi-auto versions of the MP5K with the SP5K picking up a couple of more modern features over the SP89 pistol. The newly introduced SP5K carries on these traits and adds some new ones too.
Designed and manufactured as a pistol for the civilian market, the SP5K is meant to recall the look and feel of the MP5K. (Spoiler alert, it does this in spades.) The SP5K is manufactured completely in HK’S Oberndorf factory in southwest Germany and features the same cold-hammer-forged barrel used on the MP5K, ensuring a service life of tens of thousands of rounds.
New to the SP5K are ambidextrous safety levers as well as a removable Picatinny rail for optics mounting. The handguard is also different from the other models. It was
“the SP5K features HK’S robust roller-delayed blowback system.”
made more ergonomic with added finger protection from the muzzle. With a gun this short, believe us that it’s a welcome addition. HK includes a hooded front sight as well as an adjustable drum-style rear diopter sight for targeting. For those who shoot with red dots, the aforementioned top rail is a useful new feature.
The SP5K features HK’S proven and robust roller-delayed blowback system for reliable functioning. We’ve been told that in order for HK to import the SP5K as a pistol, certain “fun” features had to be curtailed. Enthusiasts looking to replicate an MP5 may be dismayed to find that the 4.5-inch barrel is both non-threaded and non-three-lug, which means that suppressors and other muzzle devices cannot be mounted to it in stock form. The good news, however, is that the barrel mounts the same as an MP5K’S, so a compatible off-the-shelf threaded or lugged barrel can be pressed in by a gunsmith.
The MP5K also features a button magazine release similar to other HK firearms and other popular guns such as the AR-15. Again, those looking to reproduce a certain look or function of another MP5 variant can add a paddle release with help from a gunsmith.
For those who are planning to take the SP5K into NFA territory, you can fill out a Form 1 and turn your pistol into an SBR.
After it’s been SBR’D, the world of stocks is your oyster, so to speak, as any stock that would fit an MP5K will fit the SP5K as well.
Because we enjoy Sbrs—who doesn’t?— we hit up Adam Webber over at HK Parts (hkparts.net) for some guidance on how to bring our SBR’D SP5K up to speed. He sent us a host of goodies including an HK Parts three-lug barrel and paddle release upgrade kit to get us started on turning the SP5K into more of a MP5K-PDW build. The U.s.-made barrel is milled to the latest specs of the MP5K-N barrel. Its three-lugged and threaded muzzle gives us the ability to mount suppressors.
“it may have taken 20-plus years, but it was worth the wait.”
“to import the SP5K as a pistol, certain ‘fun’ features had to be curtailed.”
We turned to the experts at RDTS Manufacturing (rdts.com) for the installation of the new three-lug barrel and paddle magazine release. RDTS is a NFA Class II manufacturer and has been handling aftermarket mods on Hk-type firearms for decades. The work was quickly and expertly performed and we had a tracking number within only a few short days. We eagerly anticipated the SP5K’S return to add on a host of other accessories that we gathered for the build.
After receiving the gun back, we added an HK Parts enhanced and contoured cocking handle. The cocking handle offers twice the grabbing area for charging the firearm and is made from solid steel billet. This U.s.made part is 922R-compliant. As cliché as it might be, we had no excuse not to do the “HK slap” to charge the gun now. It may be cliché, but it is fun.
In order to fit a flashlight and foregrip, we opted to replace the new SP5K’S handguard with an M-LOK style forend, also made by HK Parts. The 3.25-inch handguard is made of billet aluminum, is a simple drop-in replacement, and has a very solid lock-up. We attached a Surefire M300 Mini Scout Light via an Arisaka Inline Scout Mount M-LOK mount, as well as BCM’S new M-LOK BCMGUNFIGHTER-VERTICAL-GRIP for greater forward control.
Some of our shooters are used to a lower cheekweld position on the gun than the stock HK optic mount afforded. Although this was a point that was not agreed upon by all, we went ahead and replaced the excellent factory mount with an equally useful MFI Ultra Low Profile Red Dot Mount anyway. The mount interfaced with our Vortex Razor red dot perfectly. We found the Razor reflex sight to be clear, compact, and durable during our time with it.
For quicker reloads we also installed an HK Parts extended magazine that attached to the paddle release. Giving the finger an oversized release to push reduces user error and helps guarantee that the magazine drops free every
time you press it. Owners of other types of guns will be glad to know that the release will fit other paddle-release-style rifles like the HK G3 and AK-47.
Last but not least on our mission to SBR the SP5K was the addition of an HK Parts PDW Telescoping Stock. This five-position adjustable stock is made in the USA and is probably the lowest-profile stock ever produced for the MP5 family. Unlike other stocks made for Mp5k-type weapons, this stock collapses instead of folds. It can be set in five positions and features stainless steel nitride-coated rails, a secure steel locking mechanism and a 7075 hard-anodized aluminum body.
Let the Good Times Roll
We handled the SP5K in as many configurations as we could. First, we had it in its unadulterated state as a pistol. In this form, it was at its most compact and easily handled, even single-handed. The 10.2-inch sight radius gave us a nice accuracy advantage over traditional pistols. The pistol weighs 4.2 pounds, so it can be a handful to keep stable after a while.
“For those planning on NFA territory, you can fill out a Form 1 and turn your pistol into an SBR.”
An included bungee cord sling is used to not only sling the SP5K when it’s not in use, but to help stabilize shots when it is. Simply wear it as you would a single-point sling, pull the gun forward, and use its “stretch” to help stabilize the weapon and reduce fatigue while shooting. It’s brilliant really. We didn’t have the opportunity to try the SP5K with pistol braces, but we imagine they would make great additions to the package.
It goes without saying that we had a ton of fun using the SP5K in SBR form. We configured it in a few ways, including with a folding stock and stock MP5K handguard as well as in the full-blown, decked-out, aftermarket build described above. We were left smiling with every shot. But what got us even more smiles was still to come.
It was then that we were presented with a Surefire SF Ryder 9-MP5 Suppressor to attached to the three-lug barrel tip. As if the day couldn’t get any better! The SF
Ryder is specifically made for use with HK Mp5-style three-lug attachments. The stainless-steel-constructed suppressor quickly attaches by way of Surefire’s Fast-attach twist collar. It is designed for sub-machine gun use, which means it performed with our semi-auto fire with utter impunity.
We attached the suppressor and went to
town. It is easily disassembled for cleaning and Surefire claims that it does not affect bullet performance or increase point of impact/point of aim. Each of our shooters was able to hit targets from a few yards out to about 100 yards with ease. The SP5K is intuitive to use and didn’t require much getting use to, even for shooters that were unfamiliar with the MP5 platform. The muffled shot that the SF Ryder provided was a welcome sound to our ears.
Worth the Wait
We’re going straight out say that we’re beyond pleased that HK has brought the MP5 platform back to our shores. It might have taken more than 20 years, but it was worth the wait. The ultra-compact SP5K is a proven firearm that is also a hoot to shoot, satisfying to collect, and just as fun to modify and configure. If we had the ability, we’d buy a few of them to make our own “HK Grey Room” at home. (If you don’t know what that is, look it up online.) One can always dream!
“the sp5k is very intuitive to use, even for shooters unfamiliar with the MP5 platform.”
The SP5K is essentially a modernized version of the SP89, which was in turn a pistol version of the venerable MP5.
The MCX is available in 16-inch barrel length carbine, 11.5inch SBR, 11.5-inch pistol and 9-inch pistol models with different caliber choices.
The MP5K was a shortened MP5; the new SP5K carries many of its signature traits and adds some new ones to the mix.
This is what we started with.
The SP5K you receive from the factory features ambidextrous safety levers and a quick detach optic mount, which are new additions compared to previous incarnations. It also comes with an ultra-compact, unthreaded, non-three-lug coldhammer-forged barrel as seen above.
After installing our three-lug barrel and paddle magazine release, we added an HK Parts cocking handle and M-LOK forend, MFI Ultra Low Profile Red Dot Mount, and PDW telescopic stock.