Century Arms' AP5-SD: The Best MP5 Clone for the Money

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I think I have to finally break down and buy an HK-designed firearm. Even before Operation Nimrod, HK firearms were hot items in the US. The HK91, the semi-auto version of the G3, had been the survivalist magazine article rifle of the 1970s, but when the SAS kicked in the windows of the Iranian Embassy in London in 1980, the firearm everyone saw was the MP5, and the HK fans had to have one. We all did. Alas, the price was astronomical, and HK wasn’t selling the select-fire ones to us anyway. It wasn’t until 1983 that the HK94 appeared, then in 1989 the import door was slammed shut.

MKE is the manufacturer, Century Arms are the importers, and the HK variant in question today is the AP5-SD, a lookalike to the integrally suppressed MP5-SD.

MP5 Clones

While the West German government was being a pain in the neck about exporting to the US (and the US was being an equal pain in the neck about imports), the 
Germans were licensing the HK designs overseas. So, that’s how we can now own HK firearms at not-nosebleed prices, from Turkey. One could say reasonable prices, 
considering what inflation has done to firearms prices in the decades since Bush the Elder turned his back on us in 1989.

Curiously, there are still some who are a bit leery of Turkish firearms. I’m not, because I’ve had several occasions to sit and talk with the engineers and management of Turkish firearms makers. They are interested in making firearms we’re eager to buy, and not in producing junk. Plus, HK licensed the manufacture of their firearms to the Turkish factories, and failing to meet Germans quality standards would get the license yanked.

The AP5-SD is a faithful facsimile of the “SD” part of the original, the suppressor part, and the rest of it is not just faithful, not just a clone, it is the real deal. Well, it is semi-auto, of course, but it is all real HK-spec’d 9mm pistol of an MP5. So, the receiver is a heavy gauge steel stamping, wrapped around a steel trunnion that holds the roller lock recesses and the barrel. The receiver has the HK claw mount bosses on the top rib of the receiver, and the cocking knob sits out front on the left side, for your retraction and then slapping to charge the chamber. The sights are HK all the way. The front is the hoop and post, and the rear is the rotating cylinder with four apertures for various distances. Aiming is simple: look through the aperture and place the tip of the post in the center. If the hoop of the front sight causes the aperture to appear oval in any way, you are not centered.

The receiver has the magazine well as an integral part of the stamped and welded shell. This is the receiver, and it is where the serial number is located, not the lower. The magazine well offers both methods of magazine change. There is the expected paddle behind the magazine, and there is a button on the right side. This is the first of the iconic HK “gestures” or methods of manipulation to mention, where the button is too far forward to be used by a normal human being. (Don’t blame me, don’t blame the Turks, blame the West German Army.) You change magazines by choking the magazine with your off hand, squeezing the mag paddle with the web of your hand. Then pull the magazine out. Oh, Century Arms sends the AP5-SD out the door with two 30-round magazines. If you want more, they have them at $70 each, which is less, even after inflation, than we would have paid for the HK originals back in the 1980s. (Yes, they were that expensive.)

Yippee Ki-Yay

To fire the AP5-SD, you move the safety/selector from the white outline of a bullet in a box with an “X” through it to the one-bullet box. Yes, you are looking at the clone of the fabled “Navy” fire control pack and its markings. The originals offered safe, semi-auto, three-round-burst and full-auto as options. Alas, we just have semi, but a very cool semi-auto, as the AP5-SD uses the dual push-pin design to assemble the trigger housing. The HK94 semi-auto carbine had the receiver modified, and the dual push pin pack could not be installed on those. Here is the second legacy HK detail: the safety lever is too far forward for human thumbs. You will have to get used to moving your hand to work the lever. This is legacy, and original, so get used to it.

On the back of the receiver, Century Arms has installed a Magpul MB BSL brace. If, however, you want to shoot your AP5-SD SAS style, push out the rear pin and pull off the brace. Then slide on the provided rear cap with loop on it. Install a sling and make it just the right length that when you push the AP5-SD out in front of you, it pulls taut just before full extension. That’s how the SAS trained to shoot the MP5 with gas masks on.

The big deal with the AP5-SD is the handguard. MKE cleanly welds a handguard shell to the receiver, and then slips a ribbed polymer cover onto the shell. This acts as the covering to the integral suppressor that the SD would otherwise have. Inside, there is a hammer-forged barrel that is 5.75-inches long, so it does not even come close to reaching out to the end of the handguard. The barrel is threaded at the muzzle (1/2x28) and MKE then screws on a hollow aluminum tube to simulate the SD suppressor.

Roller Delayed Blowback

Okay, a quick refresher for those who have been too immersed in AR-15s of late. The HK system is a delayed blowback, using rollers that wedge into recesses in the receiver. When you fire a round, the bolt thrust works (at great a disadvantage of leverage) to squeeze the rollers out of the recesses and hurl the bolt, bolt carrier and guide rod back. Since there is no rotating bolt, the HK system lacks what is known as primary extraction. To make sure the case isn’t soldered to the chamber walls when fired (and thus unwilling to be extracted), the hammer-forged barrel has the chamber fluted. The flutes allow combustion gases to flow back between the case and the chamber walls, “floating” the case to reduce friction during extraction. You can see the results on the fired cases once they are ejected.

There’s no gas system, no piston, no locking lugs on a bolt to keep clean or check for cracks. As long as the rollers can move in and out, the system works. It is remarkably unconcerned about powder type, burning rate, residues, etc. I suspect you could keep an HK 9mm running if you had to reload 9mm cases with match heads and black powder. (Probably one of the reasons the HK system was viewed so favorably back in the survivalist days)

Disassembly is easy. Unload and close the bolt. Push out the two action pins, pull the trigger pack down out of the receiver. Then grab the recoil spring assembly and pull the whole assembly out of the receiver. That’s it. No, you don’t need to remove the bolt from the carrier, and if you try you will need an assistant to reassemble the bolt and carrier, so don’t.

Operation is easy. Safety on. Load the magazine. From here, you have two paths. One, insert the magazine and lock it in place. Grab the cocking knob, pull all the way back and then release. The other path is stylish and HK-iconic. Grab the cocking knob, pull it back and then turn it up unto its locking notch. Insert the magazine. Now reach up and slap the knob, to release it and let it crash home. Fire until the AP5-SD goes click. That’s the last of the HK iconic details: it will not lock open after the last shot.

Range Results

Testing was exactly as expected, HK, and the licensed manufacturer, MKE, knows how to make an accurate barrel. The original specs on trigger pull have been faithfully maintained. The original specs for the G3 called for a loaded, safety-off rifle to survive a drop of 25 meters onto a grassy surface and not discharge. So, the AP5-SD has the HK-correct trigger pull of just over seven pounds. This, however, is not a hindrance to accurate shooting, as the test targets demonstrated. The barrel length did not add much velocity to the loads, over what we’d see from a pistol, but that is not why you get a firearm like the AP5-SD.

And that leads us to the “SD” part of things. In addition to the pistol and its magazines, Century adds in a Picatinny rail optic mount so you can install a red-dot sight on your AP5-SD. Without that, the only optics mount choice is the HK claw mount, which last I checked was fearsomely expensive (although, there is a knockoff). Century Arms makes it easy. Also, the muzzle is threaded ½-28, so if you simply unscrew the faux suppressor, you can install a real one. Or, you can use the three-lug mount Century/MKE has installed on the barrel behind the threads. So that’s what I did. I used the Gemtech Lunar 9, and tried it with just threading it on, and then replaced the direct-thread rear for the three-lug rear in the Lunar 9 and had even more fun at the range. As a pistol configuration with brace, it wasn’t quite the same outline and appearance as the original SD, but it was fun, it was quiet, and it was all-parts-in, a tenth of the price of an actual SD.

I first shot an MP5 in 1984, as I recall. Since then, I’ve shot lots of them in all configurations, including the HK94, the various G3s (even the belt-fed HK21A) but I’ve never owned one. I suspect that will change soon. Then the next episode of the journey will be: leave it as-is, or “correct” the HK iconic details like the safety lever even my thumbs can’t reach? I guess we’ll find out. What we do know is that you can have an HK-approved and properly built 9mm pistol (and some of you can even SBR it) for less cost than we would have believed in the old days. What are you waiting for?

CENTURY ARMS AP5-SD SPECS

• Type: Hammer-fired semi-automatic
• Caliber: 9mm
• Capacity: 30+1 rounds (or any MP5-type magazine)
• Barrel: 5.75 in.
• Overall Length: 30 in.
• Weight: 6 lbs. 11 oz.
• Finish: Black
• Grips: Polymer
• Sights: Fixed front, adjustable rear
• Trigger: 7 lbs. 7 oz.
• MSRP: $1,700
• Contact: CenturyArms.com

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