Understanding The HK MP5–Full Auto Review

Updated: August 18, 2015 BY Jon Hodoway

Buy an MP5 at GunsAmerica: /Search.aspx?T=mp5

Ckeck out the latest from H&K: https://hk-usa.com/UMP

MP5 SD shown with factory collapsible stock. Suppressor screws onto barrel that has slots cut into it this allows all 9mm fired to be subsonic.

The beginning

The origin of the MP5 rifle can be traced back to the final years of World War II. Engineers at the Light Weapon Development Group at Oberndorf Germany were working on a new rifle for the German army: the MKb Gerät 06. When Germany surrendered, the engineers found themselves in the French-controlled portion of Germany. The French dismantled the factory and several of the design people were brought back to France to work at CEAM on French small arms. As conflict in Indochina heated up, the French lost interest in developing a new rifle. However, in 1950, the Spanish via CETME (their state-owned arms company) used the expertise of these German engineers to develop the Modelo 2.

Several of the engineers that were not spirited away to France were left in the postwar rubble of World War II. In 1948, three former Mauser engineers, Edmund Heckler, Theodor Koch, and Alex Seidel scavenged what the French had not taken from the small arms factory and began a small machine tool plant in the abandoned factory location. This concern became known as Engineering Office Heckler & Co. They manufactured everything from machine tools to sewing machine parts.

About the same time, Germany was reconstituting their federal Army and was looking for a rifle to equip its soldiers. The Modelo 2 drew the attention of the German border guards. There was an issue that had to be solved. West Germany, as a member of NATO, insisted the rifle be chambered in 308. It became evident that CETME was not going to be able to deliver a rifle that fired the high-pressure NATO rounds. In 1956, Heckler & Koch submitted their proposal for the G3 battle rifle, which was based on the Spanish CETME rifle. The German government awarded Heckler & Koch the contract and the G3 was declared the standard rifle of the Bundeswehr.

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A schematic of a more recent HK G3, the first in a long line of formidable HK guns.

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Encouraged by their success with the G3, the engineers developed a series of four rifles based off this design. First, 7.62×51mm NATO, the second for the 7.62×39mm M43 round, the third for the intermediate 5.56×45mm NATO caliber, and the fourth type for the 9×19mm Parabellum pistol cartridge.

The fourth design in 9 mm was a reduced size G3 rifle initially designated the HK54. In 1964, work formally began on the MP5. Two years later it was adopted by the German Army Special Forces.

HK Briefcase with K gun installed note trigger on underside of briefcase handle. All rounds were kept in case upon firing. A Business card could be inserted on side of case to cover muzzle. The case itself is considered an AOW in the USA.

History in the USA

The MP5 rocketed to fame in 1980 when, on live TV, the British SAS stormed the Iranian Embassy in London during operation Nimrod. The proficient use of the submachine gun resulted in the hostages being rescued and five terrorists were dispatched. This led to a quick adoption by special units in both the military and in law enforcement in the United States. Two events, the 1989 Panama invasion and the 1990 North Hollywood shootout, caused the submachine gun to fall out of favor. The 9 mm cartridge had been found wanting and was abandoned largely for the M4 platform in 223.

MP5 Variants

The good folks at HK adopted the Burger King model of this platform: “have it your way.” I have read that there are as many as 54 variants on this basic platform. I simply think of the gun with a few basic choices that can be assembled as needed.

The MP5SD gun has an integrated suppressor. A vented barrel allows supersonic ammunition to be fired at subsonic speeds.

The MP5K is a pistol version that was considered somewhat of a personal defense weapon. This platform also has the distinction of being available with a briefcase that it can be fired from via a trigger in its handle. The briefcase will also retain all of the spent brass.

The MP5SFA2 is a semi-auto version developed for the FBI.

Several versions of this gun result from the furniture that can be attached to it. There is a fixed stock, a metal retractable stock, a side-folding stock and receiver end cap instead of a buttstock.

All of the versions above can be modified with different trigger groups. The trigger groups determine how many rounds are fired with one pull of the trigger.


Type	Positions	Settings	Location
SEF	3-position	Safe (Sicher), Semi-Auto (Einzelfeuer), Full Auto (Feuerstoß)	Left-side
SF	2-position	Safe & Semi-Auto (Fire)	Ambidextrous
Navy	4-position	Safe, Semi-Auto, 2- or 3-round Burst, Full Auto	Ambidextrous
Navy	3-position	Safe, Semi-Auto, Full Auto	Ambidextrous

The MP5/10 and MP5/40 were chambered in 10 mm and 40 caliber. These were offered primarily in response to what felt like a less than acceptable performance in the 9 mm.

Homemade version of above.

Civilian Versions

H&K was in the civilian market with versions of the MP5 beginning in 1983 and ceasing in 1994. They had two models with multiple variants that they offered in the United States.

The HK 94 represented the standard sized MP5 chambered in 9 mm with several modifications to comply with the 1968 Gun Control Act. Most obviously was the increase in barrel length to 16 inches. Less obvious and perhaps more important, the lower receiver which housed the fire control unit was no longer held on by a pin that would allow it to swivel down. Now it was a clip-on lower that was designed not to accommodate the full auto parts.

The SP 89 was a 9 mm pistol that closely resembled the MP5K. Again the lower receiver was modified to make conversion to full auto difficult.

Importation of both of these models eventually became impossible as a result of various changes to gun control laws.

MP5 K Gun with Navy Lower. Factory HK device to attach 2 magazines shown. Factory down front grip to control rise.

Clone History

The American manufacturing of clone weapons has its origins in 1986 with the Hughes Amendment, followed by the 1989 Import Ban. But the final death knoll to the civilian importation of H&K MP5 variants occurred with the Clinton 1994 Crime Bill.

I remember, in the early ‘90s, quality was sketchy, prices were high and availability was impossible to predict. Now a simple Internet search reveals multiple suppliers, competitive prices and a laundry list of options. I believe now that we have improved the platform and increased modularity in ways that never would have happened had the importation continued. Don’t get me wrong, I’m not in favor of gun control. I’m simply saying that we Americans have a way of making lemonade when the government gives us lemons.

If Star Wars has taught us anything, it is that clones can fight. Check out these reviews for more prospective on the quality of these clones.

The PTR 51: /blog/308-pistol-ptr-51p-new-gun-review/

The POF 5: /blog/pof-5/

Buy an MP5 at GunsAmerica: /Search.aspx?T=mp5

My MP5.

My Story with HK

In the late ‘70s and early ‘80s, my dad and I were involved in a sport called practical shooting that would later evolve into what we now call USPSA. One of the premier shooters in our club in central Arkansas was a gentleman some of you may have heard of named J. Michael Plaxco. Michael, being a world-class shooter, had been to a match somewhere in which one of the prizes that he was awarded was an HK 91. This was the civilian version of the G3 discussed earlier in this article.

Through some world-class horse-trading, my dad ended up with this rifle. About 15 years later, this fine German firearm became mine. There’s no other way to say it but that I developed a disease that didn’t have a cure and it could only be treated with more H&K rifles! Throughout the years I have owned the HK 93, SP89 and HK 94 along with all the more modern rifles and handguns (MK 23, USP’s, P7M13, etc.) that H&K offers.

Finally, in 2001, I purchased a registered machine gun. This gun started life as an HK 94 and was converted in Oklahoma to full auto with the three lug barrel, SEF lower and a collapsible stock. Many of my other guns have come and gone throughout the years but this one will stay with me. It represents the pinnacle of my collecting in the genre and, besides that, it’s just one of those guns that puts a smile on my face.

Buying an MP5 these days isn’t easy. You can find originals occasionally. You can buy really good knock-offs (and some not-so-good knock offs). Or you can check out the HK UMP.

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