by B.B. Pelletier

Part 1
Part 2

Umarex HKMP5-K-PDW is a lightweight, handy BB-firing semiauto.

Today, I’ll begin the accuracy testing of all three of our BB submachine guns, beginning with the first one I tested, the HKMP5-K-PDW.

This gun is semiauto only, so there are only two settings on the selector switch — fire and safe. On fire, you get one shot per pull of the trigger, which is semiautomatic fire.

The trigger-pull is long and somewhat heavy but without any creep. You just feel the movement of the trigger blade until the gun fires. Creep is that nasty start-stop hesitation in a pull that messes with your concentration, and this gun has none of it.

You may remember that I commented on the rear sight being all wrong for this gun. For some reason, the maker put notches in the back instead of the MP5 apertures. You cannot see a notch when it’s so close to your eye, and I assume some of the openness of the groups I got is due to the imprecision of the sight picture. This would have been so easy to fix in the design stage, but now it’s a hindrance for accurate shooting. Not that most people will be using the sights, which are non-adjustable. Submachine guns are meant to be fired from the hip in close assaults. They’re not a precise weapon, although I do admit that the groups that use the MP5 firearm are being trained to use the sights with great effect. But they don’t use notches this close to their eyes!

I need to make one more observation before getting to accuracy. As I loaded a fresh CO2 cartridge into the gun, the tightening screw happened to stop just after the cartridge was punctured. I wasn’t ready for it, and I lost about a quarter of the gas charge while I repositioned my hand to tighten the screw further. This is the same complaint other owners have made, only they pierced the cartridge only to have it loosen during operation. For some reason, the face seal that contacts the small end of the CO2 cartridge on this gun is unlike all others that simply swell and seal the gun instantly when the cartridge is pierced. You can overcome this by learning to hold the winding screw in such a way that you can continue to tighten it all the time, but it is bothersome.

For this test, I shot 10s round offhand from 15 feet, which is close to the distance used in international BB gun competition (16.4 feet). As I mentioned, the rear sight notch was very hard to see, and I had to hold the stock funny so I could hold my head as far back on the comb as possible. Each shot was deliberate, and I took great pains to hold the sights at six o’clock on the bull.

Crosman Copperheads
The first BBs I tried were Crosman Copperheads. They shot exactly to the point of aim, more or less, which was gratifying. I kept the six o’clock hold only because it’s more precise than trying to guess where the center of a dark bullseye is.

Crosman Copperhead BBs shot to the point of aim at 15 feet, but the group was extended vertically. Party of this is due to the difficulty of seeing the rear notch that’s placed too close to the eye to resolve. Group measures right at two inches vertically but only one inch horizontally.

Daisy zinc-plated BBs
Next, I loaded 10 Daisy zinc-plated BBs into the stick magazine. You’ll recall that Daisy BBs are ever-so-slightly larger than Copperheads. They also shot to the aim point and gave me a group that was more rounded than the Copperheads. This group measures just larger than 1-3/8″ and is wider than it is tall. So, the vertical stringing is not due to the sights like I originally thought.

Daisy BBs gave the tightest group of this test. They also shot to the point of aim at 15 feet and did not string out nearly as vertical as Crosman Copperheads.

As a surprise, I also shot a group with RWS BBs, which I told you appear to be made as uniform as ball bearings. I’m definitely going to give this BB a test for ultimate accuracy some day soon. However, in the HK MP5, they lagged behind the Daisys, due to a single flyer. I didn’t call that flyer, so we must assume the BB went where it did on its own. If we discount that single BB, the RWS BBs equalled the Daisys with a 1-3/8″ group, so I’m hopeful they’ll continue to make a good showing in future tests. Pyramyd Air doesn’t carry RWS BBs yet, but if I can give them a good reason with these tests, I know they’ll reconsider it.

A great target, if only that one shot up away from the main group can be discounted. Certainly, RWS BBs are going to get a lot more testing from me in the near future.

Overall impressions
If it had no competition, I think the HK MP5 would do very well. Its one big drawback is the lack of a full-auto burst-fire mode that the other two guns (the Steel Storm and the EBOS) have (three, if you count the Drozd). I like the trigger, and the power level is much greater than advertised. But the method of loading the CO2 cartridges requires too much work, and the sealing issue when piercing the cartridge that I mentioned in this report is bothersome. However, if you want a gun with just semiautomatic fire, this is the only BB submachine gun that has it.