Replica CO2 Airgun Collection

Umarex Steel Storm

HK MP7A1 (4.6 x 30 mm)

Info:
Manufacturer/Model: Umarex, Steel Storm
Replica Of: HK MP7A1 (4.6 x 30 mm)
Made In: Japan
Caliber/Ammunition/Feed: 177, steel BBs, 30-shot internal magazine
with 300 shot reservoir
Air Source: two CO2 12 g Powerlets
Accessories: extra piercing screw wrench
Recommended Pellet or BB: RWS Match Grade BBs (5.4 gr)
Weight (lb)/Length (in): 2.79, 15.1
Body Material/Finish/Grips: polymer, black, polymer
Barrel Length (in)/Material/Rifled: 7.50, steel, no
Trigger Action: SA only
Trigger Pull (lbs)/Adjustable: 5.2 (SA), no
Sights (front/rear): fixed, fixed
Velocity (fps): 430
Sound Level (dB): 103
Thickness of Pellet Holder (in): N/A
Manufactured Dates: 2010 - present
Condition/Manual/Box: 98%, yes, yes
Serial Number: 10D00976

Comments: Umarex, which holds the worldwide license for producing H&K replica airguns, has come up with a real winner in the Steel Storm. While the Steel Storm is not branded with H&K trademarks, it is clearly styled after the popular HK MP7A1 SMG/machine pistol. The Steel Storm is made in Japan for Umarex. The Steel Storm has a number of interesting design features including the use of two CO2 cartridges, true semi-auto operation, and perhaps the feature that will attract the most buyers, six-shot burst mode. There is no denying that this gun is a lot of fun to shoot. It is fast and powerful for a CO2 pistol but what makes it even more enjoyable is the fact that it is very accurate when used with the right BBs (RWS Match Grade BBs). It is also very reasonably priced. On the negative side, the all-plastic construction gives the gun a cheap feel, it does not have adjustable sights, and it burns through CO2 at a pretty good clip.

To load the Steel Storm with CO2 cartridges, the CO2 carrier release button (located on the left side behind the trigger guard) is pressed. This drops the CO2 carrier half-way out of the gun. To fully remove the carrier, the CO2 drop-free button must be pressed. This button is located near the bottom of the backstrap. Once the carrier is removed, two CO2 cartridges can be installed and tightened/pierced using the supplied hex wrench. Umarex designed a convenient storage compartment for the wrench inside the carrier. BBs are loaded by first filling the reservoir (capacity = 300 BBs). The reservoir is accessed by pushing the front sight toward the rear of the gun. Once BBs are in the reservoir, they are transferred to the magazine (capacity = 30 BBs) by retracting the spring-loaded follower and shaking the gun. When the magazine is full, release the follower. To fire the first shot from the Steel Storm, make sure the safety is engaged and then pull back on the cocking lever. After the first shot, gas pressure recocks the gun for all subsequent shots. Using the fire selector switch, set the gun to fire in single-shot mode or in six-shot burst mode (six shots in less than 1 second). The Steel Storm can be decocked by pulling the trigger while the safety is engaged.

The Steel Storm produced excellent test results. In single shot mode, the shot-to-shot velocities were very stable and averaged around 440 fps. Even in burst mode, the velocities remained above 380 fps and averaged 407 fps. Using a combination of single-shot and burst shooting, the Steel Storm got about 90 good shots from a pair of CO2 cylinders. By limiting the amount of burst mode shooting, more good shots can be obtained per charge. The 7.5" barrel on the Steel Storm contributed to excellent accuracy -- some of the best results I have ever seen for a CO2-powered BB pistol. In fact, even in burst mode the Steel Storm produced smaller groups than the majority of BB pistols. No jams or other failure-to-fire problems were encountered during testing with the Steel Storm. The Umarex Steel Storm is an excellent CO2-powered BB pistol and represents a real bargain among replica air pistols.

Pyramyd Air Report on the Umarex Steel Storm (Part 1)
Pyramyd Air Report on the Umarex Steel Storm (Part 2)
Pyramyd Air Report on the Umarex Steel Storm (Part 3)

Performance (single-shot mode): Measurements were made on 5/30/10 at a temperature of 78 ºF and 14' elevation. A ten shot string was fired from a bench rest at 15' using RWS Match Grade BBs (5.4 gr). The highest velocity measured was 450 fps, the lowest was 439 fps (average of the 10-shot string was 442 fps, s = 3.0). A six shot string fired with open sights grouped at 0.46". Click the thumbnail below to see a larger image. Click here for a description of the measurement methods.

A 10-shot rapid fire group (8 seconds) shot off hand with open sights from 15' measured 1.43".

Four different brands of BBs were tested with the Steel Storm. The targets below show the results for firing six-shot groups from 15' using a bench and open sights with Crosman Copperhead BBs, Daisy Avanti BBs, Daisy Precision Max BBs, and RWS Match Grade BBs.

Performance (six-shot burst mode): A six-shot burst of RWS Match Grade BBs fired from a bench at 15' with open sights produced a group measuring 0.84". The highest velocity measured was 442 fps, the lowest was 382 fps (average of the 6-shot string was 407 fps, s = 22).

Just for fun, and to show the Steel Storm's performance as it will probably be used by most owners, ten 6-shot bursts were fired as rapidly as possible from the hip at a distance of 10'. 50 of the 60 shots stayed within a 2" group.

Performance with Red Dot Sight: A Swiss Arms red dot sight was mounted on the Steel Storm and test targets were shot from a bench at a distance of 15' using RWS Match Grade BBs. These results are some of the best ever obtained from a CO2-powered air pistol firing steel BBs.


This 6-shot group was fired in single-shot mode and measures 0.28".	This group was fired as a six-shot burst and measures just 0.70".

Right Profile: The only control accessible from the right side of the Steel Storm is the cocking lever. The cocked indicator is visible through a hole on the right side.

Front View: Picatinny tactical rails for attaching accessories are located on the top and bottom of the airgun.

Left Profile 2: The front and rear sights on the Steel Storm are not adjustable. When rapidly acquiring a target, care must be taken to avoid inadvertently lining up the rear sight with one of the "ears" on the front sight instead of the front sight itself.

Right Side Markings:

Left Side Markings: The fire select switch can be clearly seen in this photo. Rotating this switch selects single-shot mode or the six-shot burst mode (6 shots in under 1 second). The cocking lever, located behind the rear sight, must be pulled back to cock the gun before the first shot is taken. Subsequent shots automatically recock the gun using gas pressure. The Steel Storm can be decocked by engaging the safety and pulling the trigger.

Loading BBs: The Steel Storm contains a 300 BB reservoir and an internal 30 BB magazine. The first step in loading BBs is to slide the front sight back to expose the reservoir. BBs are poured into the reservoir and then the front sight is moved forward to close the reservoir. To load the internal magazine, the spring follower is pulled forward and locked in place. The gun is then shaken until BBs completely fill the magazine and then the follower is released. Repeat this process to refill the magazine. Always make certain the safety is engaged when loading BBs.

Loading CO2: The Steel Storm uses two CO2 cylinders located in a removable carrier. Removing the CO2 carrier is a two-step process: 1) press the CO2 carrier release button located behind the trigger guard then 2) press the CO2 drop free button located near the bottom of the backstrap. Use the supplied wrench to tighten or remove the CO2 cylinders.

When the gas pressure gets very low, the Steel Storm will go full-auto even when the fire selector is set to single-shot. This signals that it is time to install fresh CO2 cartridges. Firing the gun with low gas pressure may result in BBs getting jammed in the barrel.

Packaging: The Umarex Steel Storm is packaged with a spare piercing screw wrench in addition to the one stored in the lower section of the CO2 chamber.