Few firearms are as iconic as the Heckler & Koch MP5. For many people, their first glimpse of the MP5 was in the hands of SAS counterterror troops, U.S. Navy SEALs, or SWAT teams. The high cost of Class 3 firearms made civilian ownership of these amazing firearms expensive—for many prohibitively so—until recently. Several full caliber and rimfire versions of popular military arms are now commercially available to the public and, for once, they’re affordable.

The first offering is from German Sport Guns. The GSG-522SD is cosmetically a close replica of the H&K MP5SD. It’s chambered in .22 Long Rifle (LR) and ships with a fixed-style stock, one magazine, a disassembly tool, an assortment of additional posts for the front sight, and the manual.


GSG-522SD (top) and Walther-HK MP5A5-22


Imported and distributed by American Tactical Imports, the GSG variants have suggested retail prices from $319.95 to $479.95 depending on the model. Most versions can be had for about $325.

Made from a high-density polymer with steel and aluminum parts where required, the GSG-522 is very light, weighing in at about 6.7 pounds. It has a polymer section of Picatinny rail mounted on the top of the receiver via two small screws. For purists like myself, it can easily be removed to give a more authentic appearance, and the polymer receiver will accept HK-style optic mounts.

Walther manufactures the other model tested, under license from Heckler & Koch. It is as close to the original as you can get without filing paperwork. Also chambered in .22 LR, the Walther-HK MP5A5-22 ships with a true-to-spec collapsible stock, one magazine, and the manual.

The Walther-HK retails for $426.25 but can be had for about $400 by shopping around. The MP5-22 comes in A5 and SD5 variants. With unloaded weight running about six pounds, the MP5-22 is lighter than the GSG-522, but by feel, it weighs significantly more. The mostly aluminum construction of the Walther MP5-22 gives it a very stout feel. This model is nearly identical to its 9mm older brother.


Ambidextrous safety selectors on GSG5 have high angles that are difficult to actuate with the thumb.



Both the HK-Walther and the GSG feature ambidextrous safety selectors and MP5-style non-reciprocating manual lock-back charging handles. The GSG safety has a high angle that I found difficult to actuate with the thumb.
The triggers both have a fairly crisp pull. According to the manuals, the HK should have a trigger pull between 6.6 and 8.8 pounds, while the GSG claims 5 pounds, 12 ounces.

My examples tested at just under six pounds for the GSG and right at seven pounds for the HK-Walther. The HK trigger has minimal take-up with a clean, solid breaking point. But the GSG has a little bit of take-up that leads into a softer, but still clean, break.


H&K ambi-safety is more akin to a 45-degree configuration and is considerably easier to operate quickly while bringing the rifle up to and off of the target.


In regard to the iron sights, the HK-Walther’s true diopter sights are significantly better than the box and post recreation by GSG. It is my understanding that GSG once offered the round diopter-style sights, but that is no longer the case. The sights they come with now are functional but nowhere near as fast and efficient as the HK-Walther sights.

GSG rear sight has no vertical limit for frame reference on the front sight. But CQB notch is an excellent configuration for short-range shooting.

That being said, the GSG sight works exceptionally well in the “CQB” setting, providing the shooter with a notch shaped like a wide U with a narrow V in the middle. This sight configuration proved to be very fast and, with a little practice, quite accurate out to 25 yards.

The HK-Walther, on the other hand, has four different sizes of round apertures, which are quick and accurate.

The GSG-522 is available with a dazzling variety of options for stocks. Available with fixed, collapsible and side-folding models, the tested variant came with a fixed stock. Patterned on the original HK fixed stock, it was very comfortable to shoot, as it gave the shooter a comfortable shoulder and cheek interface with the gun and helped create a more stable platform.

The downside is the screw-in takedown pins, which the user has to be careful not to over-tighten over the stock, because the pressure can (and will) crack the plastic stock.

The HK-Walther MP5-22 variants all come equipped with the HK standard collapsible stock. This aluminum version is considerably more rugged than the GSG-522’s plastic stock and allows the rifle to be shrunk down to a more compact package. This means your options for cases and storage spaces increase significantly. The downside is that the stock has a little vertical wobble and is not too comfortable to put your face against. But it is a significant improvement over the wire and underfolding AK stock variants.


Both versions come with a faux suppressor mounted to the barrel, and MP5-style handguards. The GSG-522SD features a rubberized rounded tube grip, similar to that on the full-size HK MP5SD.

The MP5-22 features an A5 plastic handguard that can be interchanged with any number of M1913 variants and the SureFire MP5 flashlight/laser. Some variants of Airsoft light/laser forends also fit the MP5-22, but the author does not recommend their continued use because they are not intended to hold up to the heat and stresses induced by firing live ammunition.

It is significant that both guns are also available in variants that use the SD or A5 variant of handguards and can allow the use of a variety of M1913 railed handguards. Buyer beware: not all parts are interchangeable.

GSG front sight provides lateral frame reference only for lining up the sights.

The faux suppressors and 16-inch barrels are significantly different. The GSG-522 has a stainless steel 16-inch barrel, with the faux suppressor mounting at the front of the handguard. The MP5-22 barrel is likewise stainless steel, but the faux suppressor slips down over the barrel and screws onto threads at the muzzle end.

While personal preference will dictate which is better to each shooter, no noticeable difference in accuracy as a result was detected, and neither gun showed significant deviation in point of impact from the bench.

Finally, the GSG-522 features a sling mount on the stock, but nowhere to attach a sling on the front of the rifle. The MP5-22 features the HK-style three-point sling mounts at the rear of the receiver and at the front sight, with the ability to attach the third mounting point next to the magazine well.


Both guns proved to be fantastically accurate rimfires. Out of 30 ten-shot groups fired using CCI mini-mag, Winchester bulk white box, and Federal Bulk ammo, neither gun showed anything greater than one-inch groups at ten yards. At 25 yards, the MP5-22 really shone compared to the GSG-522.

The GSG-522 still maintained impressive grouping from the bench but opened up to the point that not every shot touched the others. The MP5-22 never opened up beyond 1.5 inches and not a single shot strayed out of the group.

That said, both rifles experienced significant point of impact shift from standing to bench. The extra pressure applied to the barrels via the faux suppressors when rested on the bench caused both guns to hit between two and six inches high at 25 yards. The faux suppressors connect directly to the barrel and therefore resting them on anything pushes the barrel out of alignment with the sights.

Neither gun showed any significant functional issues until about 75 rounds into the testing. The GSG-522 presented with multiple light primer strikes indicative of a damaged firing pin.

GSG sight picture is slightly more difficult than the MP5 to acquire quickly, but is still functional inside 25 yards.

But the HK-Walther ran exactly how one would expect a gun from either manufacturer to run: perfectly. Neither rifle had any problems feeding from factory magazines, though the Pro-Mag 25-round magazines for the GSG-522 proved to be finicky until they had been fired through a few times.

The magazines for the MP5-22 and GSG-522 are not interchangeable. They have different feed lips and a slightly different curvature, with the GSG magazines slightly more rounded and the HK-Walther a little less aggressively curved.


For the money, both rifles are outstanding. If you want the best overall, go with the HK-Walther MP5-22. If you want the best bang for your buck, the GSG-522 is a good option. I’m glad I bought both.

My wife likes the GSG-522 better, while I prefer the HK-Walther. In the end, these rimfire MP5s are a ton of fun, and they throw in a bit of nostalgia for those who used them on duty or grew up seeing them in the news and every action movie.

Give them a try. You won’t be disappointed.


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