Feel the sting: building the Vz.61 Skorpion pistol.
Adopted by the Czech military in 1961 as the 7.65mm Samopal Vz.61 (Submachinegun model 1961) and later produced commercially for export, this compact weapon was designed for personal defense use by vehicle crews and security personnel. Issued at least on a limited basis by 20 countries and produced under license by Yugoslavia, it also seems to have been the darling of European terror groups including the IRA due mainly to its compact size. It is interesting to note that a friend of mine serving in Iraq in 2005 saw a Polish general officer carrying a Vz.61 around in the big holster as a sidearm.
The Skorpion machine pistol is a straight blowback weapon firing from a closed bolt. Closed bolt weapons tend to demonstrate more practical accuracy than those firing from an open bolt. Think of the open bolt M3 greasegun. A heavy bolt must slide forward to fire the cartridge when the trigger is pulled. Obviously, this movement and shifting of balance makes maintaining a sight picture difficult. The Skorpion bolt does not lock and remains closed simply by its mass and the pressure of the recoil springs. The common Ruger .22 pistol operates in a similar fashion. When the trigger is pulled the hammer is released, which drives the firing pin forward and detonates the cartridge. The rearward movement of the cartridge case overcomes the mass of the bolt forcing it back. The fired case is held against the bolt face by the extractor until it encounters the twin ejectors mounted on the receiver and is ejected upward through a slot in the bolt shroud and top cover as the bolt continues rearward cocking the hammer and encountering the rate reducing mechanism. The Vz.61 bolt is relatively light for a centerfire blowback operated weapon and that lack of mass can result in a high rate of fire so the designer, Miroslav Ribarzh, included a rate reducing device in the pistol grip to moderate bolt velocity down to about 800 rounds per minute.
The rate reducer consists of a sliding weight in a tube contained in the pistol grip as well as a pivoting hook above it at the rear of the receiver. When the bolt strikes the hook the weight is forced down into the tube riding a rod attached to the pistol grip nut. Meanwhile, the hook above it grabs the bolt delaying its forward movement. The sliding weight is returned to the top of the tube by the return spring where it bumps the hook releasing the bolt. All this action takes place in a fraction of a second and is not noticeable to the operator.
The wooden pistol grip is comfortable and access to the trigger is good even for small hands. For right handed shooters the selector lever is conveniently positioned by the thumb. The three positions are marked "20", "0" and "1". Push the lever fully forward ("20") for full auto. The center position ("0") is SAFE and the rear position ("1") is semi-auto. The markings make sense once you think about them. The safety lever is relatively small and would be difficult to manipulate with a gloved hand.
The stock is hinged at the rear of the receiver and folds forward over the top of the weapon for storage. The protective ears of the front sight retain it in the folded position. A quick slap of the folded buttstock from under the barrel is all that is needed to deploy it. It appears flimsy but it is adequate to brace the weapon against the shoulder and steady the operator's aim.
The 4 1/2-inch 6-groove barrel is pressed and pinned into a steel breechblock that is part of the upper receiver. The barrel surface is smooth with no threads or muzzle device. External diameter is .475".
The sights are much better than one would expect on a machine pistol. In fact, I found them to be too good. The large, square rear sight and protected blade front sight provide the sight picture of a 1911 target pistol equipped with Bomar sights at an NRA bullseye match. These are OK for Camp Perry but a bit slow for social work. The hinged rear sight provides two different blades graduated for 75 and 150 meters. The rear sight notch should definitely be opened up for combat use or old men like your humble correspondent. This weapon screams for a red dot sight but the top ejection port limits options.
The Skorpion is loaded by inserting a magazine and grasping the two charging buttons located on each side of the receiver. Pull the bolt fully to the rear and release. The bolt will lock open after the last round is fired. A bolt stop is located on the bottom of the receiver forward of the trigger guard if the operator wishes to manually lock the bolt to the rear.
To field strip the weapon, deploy the stock, remove the magazine and pull the bolt to the rear to inspect the chamber. Once the chamber is verified clear release the bolt and pull the takedown pin located at the lower front of the receiver. Slide the upper receiver slightly forward and rotate it open. The bolt is pulled to the rear so the cocking buttons can be removed and the entire assembly slides out of the upper receiver.
Original full-auto Skorpions are relatively rare in the U.S. Machine pistols never really caught on in American law enforcement circles and the Federal machinegun ban of 1986 precludes the many surplus weapons in Europe from being imported and sold to civilians in this country. A lot of original parts kits have made it to our shores and a few (non-transferable) full auto U.S. receivers have been manufactured.
Although this article deals with building a semi-auto pistol version of the Vz.61 from a parts kit, test firing the weapon in its original form is certainly interesting. Marc Krebs of Krebs Custom Guns had one in inventory built on a post-86 full-auto U.S. receiver and graciously allowed Firearms News to test fire it at a recent event.
My reaction to this weapon the first time I handled one was surprise at how small and light it is. It could easily be fired with one hand while the stock is folded. Obviously, the .32 ACP cartridge isn't going to produce much recoil in a 3-pound weapon and short bursts of four or five rounds produce relatively tight groups. Hand placement of the non-firing hand is somewhat problematic. The tendency is to cup the weapon in your support hand and let your thumb ride the side of the receiver but doing so will place it in the path of the reciprocating cocking button possibly causing a malfunction and/or discomfort. My solution was to grasp the receiver behind the takedown pin with my thumb and index finger. A death grip isn't necessary.
Everyone likes to fire the Skorpion. It's easy to control with little to no recoil or muzzle blast and light weight with good sights. Small statured women have no problem operating it. It is compact, easy to operate, accurate. A perfect weapon for a terrorist engaging in a swift, close range hit on a soft target. True, the .32 ACP isn't anyone's first choice for a serious defensive cartridge but a burst of three or four in the chest would certainly ruin your day. Also, think about the possibilities of adding a suppressor. The common off-the-shelf 71-grain FMJ commercial loads are usually subsonic.
Recently, we received a Vz.61 kit from the Recon Ordnance Company in Fond du Lac, Wis., (920-922-1515; reconord.com). The kit arrived on our doorstep as a bag-o-parts along with a large pigskin holster, magazine pouch, two 20-round magazines and one 10-round magazine. There were no instruction?. Scouring the 'net I downloaded an owner's manual from czechpoint-usa. com with enough information in it to assemble this thing. Previously marketed in semi-auto pistol form by CZ-USA and Czech-Point USA there is info out there. I talked to Jerry Prasser, the owner of Recon Ord, about availability of kits and receivers. They have plenty of kits in stock along with semi-auto receivers for pistol builds. Jerry has been in the import business for 40 years and he knows good quality when he sees it.
Our kit was supplied with a stripped semi-auto lower receiver imported from the Czech Republic by Czechpoint-usa, Inc. of Knoxville, Tenn. (czechpoint-usa.com). The upper receiver was received completely assembled including barrel, sights and bolt assembly. Some kits imported a few years ago didn't include the barrel but the Recon Ordnance kits are complete with the original tube. The torch-cut full-auto receiver was also included, albeit in several pieces.
The new semi-auto (SA) lower receiver is nicely machined from steel but there are differences between it and the original full-auto type. For one, the SA model isn't machined to accept the auto sear. There is no slot for it. Also, the rate reducing device cannot be installed and those parts were not included in the kit. An obvious difference is the lack of a dovetail on the rear of the receiver to mount the stock. Attaching the stock to this weapon would qualify as assembling a short barreled rifle under federal law and requires an approved ATF Form 1. The receiver is drilled and tapped to accept a stock adapter and Recon Ordnance can supply one but you need the paperwork in hand before installing it. Building the weapon as a pistol for personal use does not require federal approval. Another modification from the original military receiver is the lack of a full-auto position for the selector. The "20" position is absent.
We begin assembly of the lower receiver with the magazine catch, bolt stop and ejector. All three parts are retained in the receiver by the ejector detent. Drop the mag catch and spring into the hole where it lives in the receiver. It is keyed so you can't install it incorrectly. Insert the bolt stop and spring up into the slot in the bottom of the receiver and push in the mag catch to retain it. Insert the long ejector detent and spring down through the hole in the ejector cutout and it will retain the mag catch and bolt stop. Slide the ejector in place over the detent until it locks in place.
Gather up the trigger guard, pistol grip, grip screw (tube), grip cap and washer. The front of the trigger guard simply clips over the edge of the trigger slot in the receiver. You'll see a hole in both the guard and the receiver that line up when the guard is properly positioned. There was a rivet in that hole that was drilled out to remove the trigger guard when the original full auto receiver was removed and cut up. You could insert a small sheet metal screw in this hole if you are worried about the trigger guard coming loose. I just snapped mine in place and let it be. Install the grip tube through the loop at the rear of the trigger guard and tighten it. The flats must be parallel to the receiver so the grip will fit. This tube once contained the buffer for the rate reducing device in the original machine pistol. Slide the grip in place and seat it with a plastic hammer. Now drop the washer in place in the bottom of the grip and screw on the grip cap. Tighten it with a punch through the two loops.
Next up is the trigger group. Before we install the fire control parts we will perform a couple small modifications to convert full-auto parts into semi-auto only components. Look at the hammer. There is a small, square nub that protrudes off the right side which interfaces with the auto sear in a full auto gun. We don't need it so we cut it off flush. The full auto sear itself should be discarded. There is also an extension arm on the disconnector that we cut off with a Dremel cut-off wheel.
Begin installing the fire control group with the hammer. I clamped the receiver in a padded vise so I could work with both hands. Insert the hammer into the receiver and install the hammer pin from right to left. The receiver is counter bored for the flat head of the hammer pin so it sits flush. The trigger, sear, disconnector and connector lever are installed as an assembly on the trigger pin, Slide the hammer spring on to the hammer spring guide attached to the hammer and slide the tube protruding from the front of the sear over it. Push the entire trigger group forward and down until the ends of the trigger pin snap into the slots in the thick bosses inside the receiver. The trigger assembly is kept in place by pressure from the hammer spring. Make sure the nose of the connector lever on the left side seats into the pocket in the bolt stop. The function of this connecting or "insert" lever is to lock the bolt when the safety is on.
Once the trigger group is in place and appears to be functional install the plastic semi-auto safety lever. You will have to push up the bolt catch button to lower the tip of the connector lever so the safety can be pushed through the hole. It is keyed like the mag catch so it will only go in one way. You'll have to fiddle with it a bit but it will go in. Check it for function. The last step is to insert the hammer stop pin from left to right. This pin limits the rearward movement of the hammer.
Now we install the sheet metal retainer plate on the lower right side of the receiver. The retainer plate fits into two slots and is retained by detents front and rear. The front detent and spring serve only to lock the plate in position but the rear detents and spring serve a dual function of locking the plate and retaining the hammer stop pin. A tab on the plate also keeps the hammer pivot pin from backing out.
We received the upper receiver assembled. If you need to assemble it insert the bolt assembly into the rear of the upper receiver and install the cocking buttons with the bolt at the rear of the slots. The front pivot pin installs like the pin on an AR-15. There is a spring and detent that have to be pushed into a hole in the receiver far enough that the pin will slide into the hole. When assembling the upper and lower halves of the weapon the detent must be depressed so the pin can be backed out flush. Mount the upper receiver on the lower and slide it to the rear until it stops. The pivot pin holes in both receivers should now be aligned and the pin can be pushed into place locking the receivers together.
Our completed pistol was test fired with a mixed bag of .32 ACP/7.65mm ammo I had laying around and included Remington, Geco, Dynamit Nobel and Federal American Eagle. All test ammunition was the typical 71-grain FMJ ball load. There were no malfunctions of any kind. Average velocity varied from a low of 865 fps (Federal) to a high of 1,036 fps for the old German Geco ammo. Accuracy was excellent. Best groups at 25 yards were in the 1 1/4" to 1 1/2" range with a bit of horizontal dispersion most likely caused by my struggle to center the front post in the tight rear sight notch. I think 1-inch groups are possible. Point of impact was centered and slightly high at 25 yards. The trigger is light with some creep and breaks at 2 3/4-3 pounds. I like the Skorpion but I can't quite explain why. Overall, it is an interesting Cold War artifact.