Blyskawica: Poland's First Successful SMG Design

Blyskawica: Poland’s First Successful SMG Design

Blyskawica with folded stock.

The first pilot order was for five prototype weapons to test the cooperation network and for additional function and troop testing.  Upon the trial batch acceptance, the Diversionary Directorate of the Home Army’s HQ placed the main order for an unprecedented 1,000 domestic submachine guns to be manufactured and assembled at the clandestine workshop.  Close on the heels of this first order, a second one for 300 more was placed.  Until July, 1944, most part kits for the 1,000 SMG order were manufactured, and as much as 600 Błyskawicas were taken over and accepted by the Home Army Ordnance Command with an additional 100 assembled in July in preparation for the uprising in Warsaw.  After the uprising started, the assembling shop with most of the component stocks were evacuated to a larger armorer’s workshop, no longer secret and located in the city center.  As many as 40 weapons were completed there, the main limiting factor being – ironically – the shortage of Sten barrels, which had to be left in Teofil Czajkowski’s shop at Leszno Street, in the now German-held part of the city.

Production numbers are the subject of a heated debate.  The approximately 755 completed SMGs number has been based on the actual Home Army units’ materiel reports, some of which might be missing.  There could have been instances wherein the assembly shop workers, devoted people as they were, may have had various favors to pay for and could have stashed several guns for their own use, or hand over some of the Blyskawicas to friends in the other factions of the Polish underground, thus making the overall number slightly higher.  But even if these reports are inflated (which is highly unlikely) and the number was, say 655 instead of 755, this is still a fantastic achievement.  To invent, design, series-manufacture in clandestine shops of the occupied city and then assemble in several hundred units, test-fire and issue an entirely original model of a submachine gun to the underground army is still a marvel of organization.  Only Sten look-alikes manufactured all over Europe could compete in numbers with the Blyskawica, but none of them was of original design.  The relatively high number of the surviving Blyskawicas, some of which even got abroad (at least one as far as Prague in the Czech Republic, where for decades it was mislabeled as a German Sten copy, and another reported as far as Italy) coupled with a multitude of photographs, and even movie footage showing this little gun in action, supports the high production number.  The Uprising newsreel had a feature showing the assembly workshop at Boduena Street during the insurrection with row upon row of receivers in various stages of completion.  Unfortunately, the majority of the guns assembled prior to July were transferred to the Eastern provinces, where units were readied to stage the aborted Operation Tempest in front of the Red Army, and subsequently lost.

Ready weapons were smuggled out of the factory, 10 guns at a time, inside hollowed wire-mesh rolls.  Initially, the new weapon was restricted for the general uprising mobilization storage only, and any use of them closer than 100 km from Warsaw was strictly forbidden in order to camouflage the manufacturing area.  The overall Burza (Tempest) plan written in the winter of 1943/44 called for a general uprising rolling gradually throughout the country in front of the Soviet offensive, to disrupt German transport and defenses by tying up German forces away from the front thus helping the Soviet push – while at the same time showing the Soviets that the Polish Underground State led by the London-based Polish government-in-exile is a force to reckon with.  These plans generally came to naught, because the Soviets were unwilling to make any use of the proposed help, and treated all non-communist armed outfits in their front zone as hostiles.

The magazine well is secured with a single bolt going through a forward projection, with sling carbine hook eyelet drilled nearby.

The Home Army’s zeal to help the Soviet offensive petered out after the Vilnius liberation on July 13, 1944.  It was the first major pre-war Polish city in the path of the Red Army, and it was liberated by the joint Home Army and Soviet forces.  The liberation festivities lasted no longer than three days, after which the Soviet front troops were replaced by the NKVD who arrested all AK soldiers and deported them to Siberian prison camps.

Plans were also drawn up to liberate the capital of Poland, Warsaw, in front of the Soviet offensive, as part of the Burza.  The Blyskawica production was thus intensified in June and July 1944, with a daily output in the last days of July, reaching up to 25 submachine guns assembled, checked, and shipped to mobilization storage.  After the Vilnius fiasco, the issue of the Warsaw uprising was temporarily put on hold, but on July 22, 1944, the Soviets installed a puppet government in Lublin, the first major Polish city behind the 1939 Soviet-German demarcation line, thus clearly signifying, that they intended on permanently severing all the Eastern provinces (54% of the pre-war territory) from Poland.  This was a major threat to the survival of the nation, and a symbol was needed to mark the presence of the Underground State and boost the nation’s morale.  The uprising plans were reinstated and thus on August 1, 1944, the Warsaw Uprising broke out.

On the evening of the first day of the Uprising, parts and unfinished guns remaining at the plant were transferred to a reserve workshop, due to the heavy fighting around the original site, which became a no-man’s-land for weeks to come.  The production recommenced on August 4, and lasted till August 20, when the assembly workshop was bombed.  The last Blyskawicas made there were often lacking the aluminum barrel jacket, replaced with a simple steel threaded plug securing the barrel.

Folding stock hinge and latch holding the stock in either position.

Blyskawica from Muzzle to Stock Plate
The Blyskawica is a straight blowback submachine gun firing from an open bolt.  It has a folding stock, a vertical magazine well and is chambered for the 9×19 mm Luger round.

The Blyskawica SMG’s main component groups are: upper receiver, barrel, lower receiver, magazine well group, breechblock group, return springs group and the magazine.  The design kept complicated machining to a bare minimum with most component parts turned rather than milled and most connections made by fine-threads and machine screws, to avoid troublesome welding.

The manufacturing technology, governed by availability of the tooling and production methods, was very primitive and crude even by 1940s standards.  The guns were made mostly of the machined tubing with as few soldered sheet-metal parts or aluminum castings as possible.  Components were connected mostly by means of threads and screws, which made field-stripping a time-consuming procedure.

The upper receiver is made of the length of seamless plumbing tube, with retracting handle slot, ejection, magazine well and sear openings.  The barrel supporting plug is bolted inside the front end, while the rear one is threaded for the end cap.

The lower receiver group includes a folding stock pivot, trigger mechanism, trigger guard and a wooden grip.  The trigger mechanism is a self-contained entity, inserted as a whole into the lower receiver – exactly like in HK weapons.

The magazine well is welded of the two halves, with a magazine catch assembly screwed to the back of the housing.  A projection of the magazine catch external frame extends inside the receiver to serve as an ejector.  The magazine well is fastened to the receiver with two bolts.

Bolt in closed position. Note the bolt handle.

The barrel is 197 mm long, patterned after the Sten and made fully interchangeable, having six lands and grooves with a right hand twist.  It is inserted into the barrel plug and then secured by screwing an aluminum barrel jacket on top of the barrel retaining collar.  The Sten type barrels were mass-produced by the Teofil Czajkowski’s workshop in Warsaw, along with other 9mm barrels.  The quality of Czajkowski-made Sten barrels was dependant on available steel grade, but manufacturing standards were usually better than the original – especially the two-groove Mk 3 barrel.

Blyskawica has a heavy (720 gram), massive breechblock with the feed/extractor channel and sear notch cut in the underside, and a hollowed-out rear, where a driving spring with its guiding/dividing tube fits.  The firing pin is rigidly installed in the bolt-face, as in the Sten.  A dove-tailed channel for the retracting handle base is cut on the outside of the bolt.  The breechblock is machined out of solid steel rod with driving ribs machined along it to ease friction and channel the dirt, much like in post-war George Patchett’s Sterling SMG.  The ribbed bolt is in fact a reversal of the MP 40 layout, whereas the bolt is cylindrical, and the receiver tube is corrugated to form the ribs for the bolt to glide along.  This feature was very highly rated by the Polish designers examining the captured German SMG, but limited production resources prevented copying that.  With no sheet metal die-pressing technology at their disposal, Polish designers had to devise something ingenious to retain the useful feature, while at the same time keeping the technology as simple as possible.  Blyskawica receivers were made out of length of seamless tubing, much stouter than sheet-metal, so the pressing of the ribs was out of question.  Wielanier then proposed a logical alternative: if we can’t groove the tube for bolt interface, let’s groove the bolt for tube interface.  And so the designers reversed the procedure.  After turning the breechblocks on the lathe, these were moved to a milling machine and ribs were machined along it, resulting in a ribbed breechblock and a smooth inner receiver.

There is another feature also strikingly resembling the Sterling: a dual concentric return spring dubbing as a buffer.  The longer (320 mm) outer spring of 22 mm diameter acts as a main driving spring, while the much shorter (110 mm) bumper spring of 15 mm diameter cushions the bolt in the rearmost position and helps it gain initial momentum for the next cycle.  The bumper spring is inserted inside the guiding tube of the receiver plug, dividing it from the return spring resting on the outside of it.  As with the bolt ribs, the dual springs arrangement was also a part of the MP 40 legacy rather than having anything in common with the Patchett, whose development was completely unknown to the Polish designers at that time.  The spring telescope of the MP 40 contains two springs – a longer mainspring, and a much shorter bumper spring installed into the front portion of the telescoping mainspring cover, with a bumper casing incorporated into the firing pin base.  Reproduction of the spring telescope was out of question due to the complexity, and the general redundancy of it.  Again, something simpler was needed, and again, the answer was to reverse the MP 40 idea.  Both springs were installed in the rear part of the receiver, with the outer return spring fitted around the receiver end cap/spring guide, and the inner bumper spring inserted into it.