I was first introduced to KRISS USA, the North American extension of the Switzerland-based KRISS Group, a few years ago at SHOT Show. I was impressed by what the company had to offer in the way of quality and innovation, so I took the Sphinx Compact Alpha 9 mm pistol for a test drive. Since then the company has been working to expand the caliber options of its Vector line-up of carbines, submachine guns and pistols. Recently, it released the Gen II series which includes options chambered in 9 mm. This review takes a closer look at the SDP 9 mm pistol.
The SDP is a semi-automatic pistol fitted with the patented Kriss KSV closed-bolt, delayed-blowback action. This particular model has been configured as a non-NFA item for sale on the U.S. market, thus no shoulder stock. However, the rounded flush cup (QD) sling swivel mount can be removed and replaced with a shoulder stock should the gun owner wish to register the SDP as a short-barreled rifle (SBR) with the federal government. 
The Kriss Vector design stands out from other pistol-caliber platforms because of its unusual, but effective, Super V Recoil Mitigation System. Most semi-automatic rifles and pistols employ a recoil system that moves backwards (directly towards the operator) as just-fired casings are ejected. The resulting recoil tends to flip the muzzle of the gun up and away from the target.
In order to reduce muzzle flip, the Super V Recoil Mitigation System utilizes a bolt attached to a recoil assembly that moves downward (toward the ground) instead of directly back. The system is positioned in a space behind the magazine well, which explains the Vector's somewhat boxy shape. This recoil system configuration has other advantages. It eliminates the need for a complicated gas system. It places most of the gun's weight directly in front of the grip for better balance. And because the recoil system is not located across the top of the gun (like an AK-47) or behind the action (like an AR-15), the Vector can be configured in a variety of barrel and stock lengths. 
The SDP's two-part chassis is constructed of a tough black nylon fiber composite polymer that is treated with a Cerakote finish to give it the OD green color shown here. Other color options include Flat Dark Earth and Alpine White. It's topped with an integral aluminum sight rail which arrives fitted with a set of removable Magpul MBUS polymer sights. A 3.5" accessory rail, below the barrel, can be used to attach lights and lasers. 
The muzzle of the 5.50" barrel is threaded at 1/2-28" TPI and will accept 9 mm AR-15 pattern muzzle accessories and arrives with a thread protector installed. The non-reciprocating, left-side charging handle folds forward against the receiver when not in use. The serrated bolt-catch lever, located just below the charging handle, is easily operated with the thumb of the support hand, as is the magazine release button. The Vector series is designed to load from Glock magazines. In the case of the SDP 9 mm, it accepts G17 pattern magazines with capacities of 10, 17 and 33 rounds.
The ambidextrous thumb safety lever is positioned above the integral pistol grip. It swings down into the Fire positions and back up into the Safe position. The Gen II smooth-faced steel two-stage trigger has a light 1 lb. takeup and breaks cleanly at 4 lbs. 5 oz. of trigger pull with just a hint of travel after the break. The trigger reset is short with a tangible and audible “click.” The grip features a storage compartment with a hinged access plate and the integrated QD sling swivel mount arrives with a swivel installed. Unloaded, the pistol tips the scales at 6.20 lbs. with an empty G17 magazine inserted. 
The pistol's upper and lower polymer receivers are held together with four takedown pins that can be removed without tools. Field stripping the gun starts by removing the magazine, locking the bolt in the open position to verify that the gun is completely unloaded, and then moving the bolt forward into battery.
Remove three of the takedown pins, the two up by the sight rail and the one located nearest the pistol grip. Separate the upper and lower. Now remove the forth pin, behind the magazine well, and pull the recoil assembly down and out of the receiver. Rotate the bolt to remove it from the recoil assembly and the pistol is ready to clean. The SDP goes back together just as easily.
There wasn’t much information in regard to ammunition compatibility in the SDP's owner's manual, so I called a company representative for more information. Kriss recommends that Vector 9 mms be fired with ammunition loaded to at least SAAMI specifications. This is because light target loads or hand loads may not cycle the robust, combat rifle-type action reliably. The Vectors have been tested extensively with +P 9 mm and have not shown signs of distress or excessive wear. 
At the range, the SDP ran reliably with every type of ammunition it was fed. Test loads ranged from bulk 115-gr. full-metal jacket practice rounds up to +P hollow points. Test magazines included the Glock 17-round magazine provided with the pistol and a set of the extended 33-round SGMT9G33R magazines manufactured by SGM Tactical. This was my first opportunity to work with SGM magazines and I found them to be solid and reliable. I'm looking forward to trying them in a few more guns.
The 6-lb. weight and recoil reduction system gave the pistol an almost gentle disposition in the felt recoil department. All of the other controls worked properly, although the charging handle was stiff enough that I had to grasp the front of the lower receiver with my shooting hand in order to have enough leverage to cycle it. It's not a deal breaker per se, but it is something to keep in mind.
For off-the-bench shooting, an adjustable braided paracord Sandstorm Custom Rifle Slings convertible sling was attached via the QD sling swivel port. Creating a push-pull tension between the sling and the pistol helped to steady it for standing shots. 
Formal accuracy testing was conducted from a benchrest by firing five, five-shot groups into targets set at 25 yards using the provided folding sight system. The HysKore adjustable #30207 Rapid Fire Precision Shooting Rest, which I’ve found to be helpful during other rifle-action pistol tests, proved to be a very good option to stabilize the atypically shaped SDP. There was plenty of room for the 33-round SDM magazines. Bullet velocity was checked using a Lab Radar chronograph. 
Test loads included Federal American Eagle 147-gr. full-metal jacket, Hornady Custom 124-gr. XTP, and HPR Hyperclean 115-gr. full-metal jacket rounds.
Overall, bullet velocities were on par with other semi-automatic 9 mm pistols with barrels that are around 5" in length. However, the accuracy was better than the typical defensive pistol with groups hovering around the 1.50" mark.
The new Kriss USA Vector GEN II SDP 9 mm is a rugged, reliable semi-automatic that rifle-action pistol fans will find to be fun and affordable to shoot on and off the bench. Although trimmed-down, pistol-caliber combat rifle actions like this one are not everyone's cup of tea, the Vector's features and recoil reduction system make it an innovative and unique option. The system works nicely in the carbine configurations too.
NRA Specifications
Manufacturer: KRISS USA
Model: Vector GEN II SDP ODG
Action: Closed Bolt Delayed-Blowback Semi-Automatic
Caliber: 9 mm
Steel Components: Matte Black Nitrite Finish
Stock: Black Nylon Fiber Composite Polymer with OD Green Cerakote Finish
Grip: Integral with Storage Compartment
Sights: Magpul MBUS
Barrel Length: 5.50"
Muzzle Thread Rate: 1/2-28" TPI
Overall Length: 16.75"
Height: 6.75"
Weight: 6.20 lbs. with Empty Magazine
Magazine Type: Glock G17
Capacity: 10+1, 17+1 or 33+1 Rounds
Twist: 1:10” RH.
Rifle Grooves: 6
Accessories: Hard Case, 1 Glock G17 Magazine, Owner's Manual, Lock
MSRP: $1,429
