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HOW TO HANDLOAD SUBSONIC RIFLE
Part One: Remembrance and Grey Theory
By: P. T. Kekkonen (1999)
Written for on-line magazines "Gunwriters on the Web" and "Firepower", along with the book "Silencer History and Performance", Volume 3. Permission confirmed in March 4th 1999 by author, PTK.
Author has played with subsonic centerfire rifle handloads since 1974 -- yes, quarter of a century -- being still alive. Frustration of many cartridge manufacturers, powder producers, bulletmongers and many other authorities on handloading has been easy to understand: Many peoples have a loathing for idea that all the folks can handload subsonic ammo! Many others are without prejudice: They need just know-how...
Reduced charges for Rimmed Russian rifle cartridges 7.62 mm Mosin-Nagant the author used a quarter-century ago in his old battered Winchester Model 1895 "Angliiskiy Zakaz" rifle, made for Imperial Russia during First World War and captured by patriotic Finnish Civil Guard during the First Finnish Independence War in 1918.
Author could obtain just old "war souvenir" cartridges, because he hadn't permission to possess that Winchester, and so it was impossible to get license for buying of 7.62 x 53 R cartridges either. Along with one lot of cartridges he got several hundreds rounds of Russian 7.62 x 25 mm submachine gun ammo into the bargain.Many rifle cartridges with 9.6 grams Spitzer bullets contained spoiled powder charge, but the primers were functional.
7.62 mm Tokarev ammo were in very good condition, but author had no firearms for shooting with 7.62 x 25 mm cartridges. He had a lot of rifle brass with good primers along with salvaged bullets, but not rifle powder, and handloading data, or even the reloading equipment, except bullet-removing pliers. He had pistol powder in Tokarev cartridges, charges 0.54 or 0.55 grams behind bullets, weighing 5.5 grams.
Sometimes in 1974 or '75 he took the liberty to load some rifle shells with a single charge from a " Russian submachine gun cartridge" and the bullet of Soviet submachine gun. In those days it was strictly disapproved to use nothing but rifle powder in rifle loads, and nothing but pistol or shotgun powder in handgun cartridges. These warnings were printed on the booklet "Metsästäjän Opas" (" Text-book for Hunters "), published by Finnish Central Organization of Hunters. Fortunately enough, the author had not read that book. Shooting of 5.5 grams bullets with one tenth charge-weight of handgun powder was a very pleasant experience: No nasty kick! No loud boom ! Just a crack, similar to that of .22 rimfire rifle, loaded with supersonic RWS, or FIOCCHI's .22 LR Hollow Point cartridge.
Author hadn't a powder scale, but it was rather easy to divide the powder charge in two. Sound of report was now about as noisy as "cra-lack-clunk" utter of lever action, but accuracy of bullets was no more satisfactory. Muzzle velocity varied too much between shots. Author noted also hangfires, and when one bullet lodged the bore, he noted 0.22 - 0.23 grams charges to be strictly "sub-minimum Suggested Start Loads". (Nowadays, when author is twice as old as in those days, he don't dare to shoot 5.5 grams bullet with bi-metal jacket, loaded with less than 0.40 grams charge of Soviet silvery-kerneled handgun powder, from any 7.62 x 53 R caliber firearm, including MAXIM machine gun).
Author dared also shoot some shots with doubled 7.62 mm Tokarev charge. They developed pressure about as high as usual factory-loaded cartridges. Next step was shooting with charge of 7.62 mm Tokarev cartridge and salvaged 9.6 grams rifle ball.
Fair accuracy; erratic noisiness
Some bullets were jacketed with nickel-plated mild steel jacket. (They clung on the magnet. Bullets with cupro-nickel or "melkhyor" jacket don't cling). Some other bullets were covered with copper alloy jackets. They were presumably Finnish-made balls S-30. Diameter of steel-jacketed bullets was never more than 7.80 mm: They were slightly too thin even for .308" bores of Western rifles. Groove diameter of Russian rifle may be as much as .311 inch or 7.90 mm in factory-fresh bore. (So it was in author's slightly corroded Winchester M/95 Angl. Zakaz).
Loads gave acceptable accuracy, but the sound of report was very fickle: Sometimes dull and mild "pooh" and sometimes more sharp "crack". In the early 1975 had the author not yet a chronograph in his use.They were rare and expensive gadgets, before introduction of OEHLER Model 12, bought by author in the late year 1980.
"POOH" and "CRACK"!
Not too many Finns understood the difference between SUBsonic and the SUPERsonic projectile in 1975, and the whole World learnt a new word TRANSsonic after 1992, when a table "BULLET FLIGHT NOISE VERSUS VELOCITY" was made public, firstly in Finland.
Soviet-Russian .22 LR "VOSTOK Sport & Hunting" cartridges were common fodder of inexpensive TOZ rifles in Finland during 60's, until 80's. Many users of these cheap cartridges distrusted them, because of fickle shooting noise: "Some cartridges sounds like an air rifle. Others cracks like a strike of a thunderbolt ...! Muzzle velocity variation MUST be at least a hundred meters per second !"
Actually it was less than 10 m/s, but if a bullet emerges the muzzle with a velocity 345 m/s and next one at velocity 336 meters per second in ambient temperature +15 degrees Celsius/ Centigrade, is difference of audible signature easily noted, even without presence of suppressor/silencer, but especially when a "sound moderator device" is mounted. (Some TOZ M-8 or M-12 rifles were equipped with so-called "NURKKALA's Suppressors" - and some others with a much more quickly detachable "Poacher's Suppressor" with a 19/22 mm brass tube jacket; designed by the author in late 1970s).
Glossary of silencing
When a subsonic bullet - with a velocity just a bit less than velocity of the sound in ambient air - is shot through a noise-reducing device, it is SUPPRESSED. In the luke-warm day of Finnish spring, when the temperature is +15 degrees Celsius, is this "sonic velocity" 340 meters per second, and Mach 0.9 reading 306 m/s. (Mach 0.9 equals 90 % from sonic velocity in measured temperature of ambient air).
If the bullet velocity is 90 % or less from velocity of sound in the air, and the noise-reducing device is well-designed, the shot is SILENCED. (The author has since late 1970s called that ideal situation as an ABSOLUTE SILENCING).
When the muzzle-blast of shot is muffled or eliminated, but a flight noise of projectile is transsonic or supersonic, is the suppressor just a "SOUND MODERATOR" - despite of its ability to eliminate muzzle-blast, and other signatures of shooting - like muzzle flash or blowing of the powder gases. A well-designed suppressor may be a silencer or sound moderator or something between these extremes - depending on projectile velocity.
Silence without silencer
Sometimes the muzzle-blast is a "whisper" even without presence of suppressor device. .22 rimfire rifle with an extra-long barrel (length more than 600 mm / 23 ½") can be very quiet, when loaded with CB Short or Long cartridge, also known as ZIMMER-load or simply Z-cartridge. German word "Zimmer" means "room" or "indoor". Z-loads are intended for gallery practice, but they are useful for pest control or even for small-game hunting. Light bullet, with muzzle velocity not very much more than 200 meters per second, is more lethal than most of peoples dares to believe - or even to dream !
Original Z-loads hadn't powder charge at all, but just a priming pellet slightly more powerful than needed for normal rimfire cartridges. Frenchmen FLOBERT and HOULLIER developed the first versions of them, BB-caps, CB-caps and Bosquettes, during the first half of 19th century. Usual .22 Short or Long Rifle standard velocity cartridge, with a nominal muzzle velocity ca. 340 to 360 meters per second, may be quiet when shot from some rare .22 rifle with a VERY long barrel.
A quiet old "Long Tom"
Finnish Army used some decades ago .22 rimfire rifles, exclusively chambered either for LR or Short cartridges, with barrel length almost amazing, 825 millimeters (32 ½ inches!) When loaded with standard velocity.22 LR Vostok cartridges or Lapua Championships (nominal muzzle velocity ca. 340 m/s), the muzzle blast was as noisy as that of SHERIDAN's compressed-air rifle, pressurized with five or six pump piston strokes. Bullet's flight noise was always absent.
Reduced pressure AND velocity
When loaded with .22 Short cartridge, made for Olympic Pistol shooting (= Rapid Fire Match), the hit of "Long Tom's" heavy striker was a dominant sound. Then came snap of bullet from direction of the target. It was also possible too see, even without magnifying optical sight, the slowly flying bullet. Nominal bullet's muzzle velocity of these .22 Short Pistol Match cartridges was 310 m/s, shot from 4" test barrel.
Author hadn't yet the chronograph in late 70s, when he became acquainted with that rare variation of Mosin-Nagant model 1891, but velocity of bullet might be approximately equal with that of similar .22 Winchester Long-Z bullet, shot from usual rifle barrel; length 20 to 22 inches.
Extra barrel length = a suppressor
Extra ten inches or one full foot of barrel and bore length is able to act as a suppressor. Volume of the extended bore shall lessen the pressure of powder gasses emerging muzzle. Friction between rifled bore and the bullet slows down muzzle velocity; Q.E.D...
When using Standard Velocity .22 LR ammo, the bullet velocity is increasing to ca. 400 mm (16") distance from the chamber, but after passing this culmination point, is the velocity decreasing, because bore friction shall overcome the thrust of powder gasses, pushing the bullet towards gun muzzle.
Bore pressure is decreasing, because volume of the bore behind the bullet is expanding and temperature of gasses is declining. Barrel metal absorbs the heat, and rapid decrease of the bore pressure cools also powder gasses down. "Diesel Effect" can be reversed too..!
Same old Laws of Physics
"Why all this long-winded sermon about Gallery Rifles and Zimmer-cartridges ? Nobody is able to reload .22 rimfire cartridges !"
It is true, dear Hard-Core Handloader, but millions of gun-nuts all-round the Globe
knows just .22 RF non-Magnum rifle as a gun, able to become silenced, or "silent
without silencer" gun, if loaded with proper cartridges.
Centerfire rifles are subjected to the very same Laws of Physics as is the gallery rifle. There was also know-how for handloading of gallery practice cartridges for military rifles in Finland. Loads were called as "Kissan aivastus", id est:
"The Cat's Sneeze"
Once upon a time were American buckshots No. 1 Buck, and/or British shots Special LG, plentifully available in Finland. Diameter of both sizes is 7.62 mm or .300 inch; nominal bore diameter of .30 caliber and 7.62 mm rifles, including those with "Russian rifling". (Actually Belgian, for Argentine 7.65 mm Mauser rifle. Difference of bore diameter was just nominal).
Finnish Civil Guard or National Guard (Suojeluskunta) had still many Russian Mosin-Nagant rifles, captured from Russians and Finnish socialists during the First Finnish Independence War in 1918, or bought from Imperial Germany before that war.
Mixed bag of Mosin rifles
Russian rifles were also obtained by swapping from Poland, which adopted caliber 7.9 x 57 mm Mauser after their own independence struggle in 1920. Polish government had captured Russian firearms, while Finnish cavalry had Mauser carbines. Both countries wanted rifles just with one caliber.
Groove diameter of Russian rifles is "considerably variable". (This notice on many reloader's handbooks isn't exaggerated !) Some wealthy Finnish Civil Guardsmen made things still more difficult: They bought barrels with Western rifling dimensions for their rifles, for use of most accurate British or American bullets in shooting competitions. Groove diameter of rifles could now be anything between 7.80 and 7.95 mm (.307 - .313"). Bore diameter was more uniform. Spherical soft lead bullet of "cat's sneeze" gallery load was dimensioned according to it.
Something old; something new...
Gallery cartridges with round lead bullet were well-known everywhere in late 1920s, but the soft lead ball (or one cast from more hard lead alloy) was usually bigger than a groove diameter of the rifle bore. IDEAL MANUFACTURING Co. recommended .311" diameter round ball moulds, yielding bullets: "snugly fitting in the 30 caliber shells", suitable for "short range indoor work." Factory-made lead ball, as big as Number Zero Buckshot (.32 "/ 8.13 mm) could be used in .30 caliber rifles.
The author has shot more than a hundred 8.0 mm / .315" pure lead balls, made by HAENDLER & NATERMANN, from .308 Win. STEYR SSG rifle and TIKKA M-55, also .308, up to a hundred meters in the outdoors range. Accuracy was very good in calm weather. Powder was very rare Finnish VIHTAVUORI's Blank Powder N 312; never available for handloaders and discontinued in 1980s. Charges were twenty kernels of N 312; presumably ca. 0.20 grams (never weighed). There wasn't even a dipper in use. See Arcane part 2 for more details.
With or without powder
Cat's sneezes of Finnish Civil Guard had the bullet weight like that of usual .22 LR rimfire cartridge, but because of bullet shape, the range and penetration were considerably less than those of the "gallery rifle" loaded with "full-length" cartridge. (Archaic names of .22 rimfire rifle and .22 LR ammo). Sneeze-handloads for 7.62 x 53 R cartridges were loaded into spent cases, previously shot in user's rifle with full-power charge, id est: "fireformed". Cat's sneezes could not be factory-loaded. They were exclusive reloads.
Loading tools and dies were unnecessary equipment, except a chisel or awl for tearing off the spent Berdan primer. 7.62 mm Mosin-Nagant cartridges with Boxer primers were uncommon luxuries in 20s or 30s. After re-priming was the very small charge of FFFG-grade black powder or DuPont's Schultz Shotgun Powder measured into each case with a dipper, made usually from a spent pistol case.
Primer as a propellant charge
For a short range indoor work, to ten or fifteen meters, the powder charge was found unnecessary at all. Especially the large Berdan No. 1 primer (made in USA) or British Kynoch No. 41 were powerful enough to spit the lead ball into target. Diameter of these primers was 6.38 millimeters or .251". The large, shallow spent primer was easy to remove, with a chisel or water-pressure. US-made Berdan No. 1 and Eley/Kynoch 41 primers were fit for captured Russian cartridge brass too. Fit was loose enough to allow repriming with a thumb-pressure, because primer pocket was dimensioned for still more large Russian primers.
De-capping was many times possible by knocking the case head on the table or other hard, smooth surface. Extra-large primers, with diameter 6.45 mm or .254" were made by VIHTAVUORI for use in "everlasting" brass shotshell cases. Cup of these "Spade primers" was of copper, and thin-walled. It was snugly-fitting into priming pocket: It didn't leak, but was accordingly more difficult to de-cap than Berdan No. 1 primer.
Gliding slippery leaden pill
Lead buckshot was caulked or sealed into case neck with a wax or thick axle grease. If the powder charge was used, it was a common practice to push a tuft of kapok or cotton on powder. This wadding kept the charge in the rear-end of loaded shell, and it prevented bullet lubricant contamination of powder and primer. Soft lubes, axle greases, weren't uncommon and priming compositions are extremely sensitive to grease or oil. Very slight dose of grease is able to spoil primer, making it inactive. (Nowadays is the most popular wadding material an "artificial kapok" known as DACRON, which melts in the heat of powder or primer flame, and flies out from the muzzle behind bullet as a tiny pellet - not bigger than a barley corn. Dacron wadding is safe to use even in cartridges of suppressor-equipped rifles). Contrary to the groove-sized bullets, the bore-sized buckshot glided on the fields of rifling, just like a rocket glides on rails in the barrel of German Nebelwerfer, or Panzerschreck (bazooka; Ofenrohr) rocket launcher
Slow rotation from rapid twist
Pea-sized slippery projectile gained just a very slow rotation in the bore, despite of rapid twist of rifling (= 240 mm or 9.45"). But ANY rotation is able to stabilize spherical bullet by preventing of revolvings to non-descript directions, if the leaden sphere is free from asymmetric voids or faults. Neck of the un-resized case for a "Kissan aivastus" cartridge was usually filled full of lubricant, which prevented leak of powder gasses past the bullet, and it lubricated bore wall for the next shot.
Bullet lube made also bore cleaning an easy task, even when cartridges were charged with black gunpowder. Lead fouling of the bore was unusual occasion, despite of soft bullet material: pure lead. If some fouling was noted, was the powder charge re-adjusted by trial-and-error method.
Leaded bore = careless reloader
Sometimes the mildest gallery loads (primer only) leaded the bore. Little "booster charge" of powder, along with use of wadding, was needed. Use of "war powder" was - of course - an unwise or even risky way to load sneeze-cartridges. ("War powder" was rifle powder from disassembled cartridges). Just black powder or "hunting powder" were allowed, as well as pistol powders. There wasn't luxury, like published reloading data, available in Finland during years of The Great Depression, but accidents with Cat's Sneeze cartridges were never (?) happened.
Too heavy powder charge punished daring handloader by badly lead-fouled bore (and extra toil of bore cleaning) even when the chamber pressure was barely half from 3100 atmospheres, id est: maximum allowed pressure of 7.62 mm fighting cartridge. (Actually it was impossible to over-load cartridge with a 40 grains lead ball and black powder or DuPont Schultz).
For any & all .30 caliber rifles
"Why all this babbling about Finnish history and ancient Russian rifles ? Why this nagging about some Depression Era handloads for Mosin-Nagants model 1891 ?"
Dear Hard-Core Handloader! While this know-how was published once upon a time by a Finnish periodical magazine of the Civil Guard - "HAKKAPELIITTA" - it is nowadays a fragment of almost forgotten folklore in Finland. We have no more No. 1 buckshots available as inexpensive "in bulk" merchandise. (Era of The Great Depression was more rewarding in many respects than is modern Era of Abundance..! Almost seven decades later must a poor Finnish rifleman gather mushroomed .22 LR bullets from a shooting range and roll them spherical in a device like 17th Century "shot mill", if he needs just some loose buckshots No. 1 Buck; not 2.3 kilograms bag of them as an air freight from USA).
Know-how to reloading of "Cat's Sneezes" may be useful for millions of gun-nuts using .30 caliber or 7.62 mm rifle; not just owners of Mosin-Nagant. (Action of the rifle must, however, be able to feed un-resized spent cases into its chamber without violent thrust forwards, preferably by manual chambering and slow closing of the action). For "short-range indoor work" it is possible to try as "hot" Magnum Rifle primers as one can get. Don't forget the bullet lube ! It is the "discarding sabot" of this kind of cartridge. Use of wadding (Dacron) is recommended even for the " gallery loads"; those without powder at all.
Powder choose is easy
Although the very best powder for "Kissan aivastus" loads is no more available (and presumably it was never sold to reloaders: EXPLOSIVE COMPANY's E.C. Blank Powder), a powder choose is still simple and safe: The VERY MOST fast-burning or "hottest handgun propellant of manufacturer's or importer's selection... Examples: Bullseye, Red Dot, HP-38, Clays/Universal, N 310.
The first and the last mentioned powders have a long career as propellants of reduced-charge rifle cartridges: LAFLIN & RAND's original "dust" Bullseye has been used for special purposes a century ago, and "disc" Bullseye of HERCULES dynamite factory was used for charges of .30-06 Cartridge Guards with 150 grains jacketed bullets before The First World War; (The Big). Finnish VIHTAVUORI's N 310 was earlier known as N 14, and it may still be N 14 in Army nomenclature. Unofficial pet-name is PaPP powder. (PaukkuPanosPatruuna = Blank Cartridge).
Fuels for the heat engines
Powders, mentioned above, are double-base propellants, except N 310. It is single-base or nitro-cellulose powder with added inorganic oxygenating salt; potassium nitrate. N 310 can be called as porous, semi-smokeless multi-purpose propellant. Double-base powders contains nitro-glycerol as an added oxygenating element, which raises combustion temperature of powder and so adds contemporarily the volume of powder gasses. "Calorimetric energy" of powder is rather high. One gram of Bullseye powder generates ca. 5000 Joules energy. It equals kinetic energy of high-power Magnum big-game rifle bullet at close range!
But, alas, machines for projectile throwing -- also known as firearms -- are heat engines with a certain coefficient of efficiency: ca. 33 per cent. Just one third of calorimetric energy shall become utilized for the work. From 15.43 grains or one gram charge of Bullseye it is possible to get ca. 1670 Joules as a kinetic energy of payload -- bullet or shot charge.
(From handguns, like .45 ACP Colt Model 1911, is available ca. 30 % efficiency -- or slightly more than 1600 Joules per one gram of Bullseye powder, because of rather low allowed chamber pressure). Calorimetric energy of N 310 is ca. 4100 Joules per gram. Not so poor performance of single-base semi-smokeless powder. Many "strong", really smokeless, rifle powders yields no more than 3500 or 3600 Jpg in calorimeter.
The nitre, or saltpeter (potassium nitrate) is main element of black gunpowder. The black powder is presumably still the least sensitive propellant to variable ambient temperatures, especially the icy frost. During the World War II had Germans so-called "DiDi-Pulver" (with added di-nitro-di-ethylene-glycol) for use in artillery pieces and NP-Pulver (with added penta-erythrite-tetra-nitrate) for rifle-caliber machine gun ammo, loaded for air forces, yhe famous Luftwaffe.
Both of them were claimed to be as immune to frosty weather as black powder, but no handloader is able to buy "DiDi" or "NP" from local sporting goods store. Composition of them may still be "classified" ?! Usual double-base powders have nasty habit to "freeze" in a cold climate. They are "fine-weather powders", fit for use in dzhungle of East-India or savannah of Africa -- and, of course, for indoor gallery practice.
In the tundra or taiga of Siberia, or sub-arctic Finland (where all intellectual life seems to be hibernating since September until Mayday) are all-weather powders needed. They are single-base powders with cylindrical or tubular kernels, or square flakes. Powders for shotshells and handgun cartridges (or "general-purpose powders" according to the author) are usually "washed" to become porous-surfaced like an exposed-aggregate concrete.
Kernels like a sponge
All the Finnish general-purpose powders of series N 300, and rifle powder N 110, are made porous by blending the pulverized water-soluble salt into gelatinized "dough" of nitro-cellulose and Hoffmann's Mixture (ether-alcohol), acetone, or acetidin. When the dough is extruded, chopped and dried to solid state, it is washed in the hot sweet water, which removes particles of the salt away from surfaces of powder kernel, so leaving it pock-marked or looking like a sponge. Surface area of tiny powder kernels is multiplied, and the sponge-like surface renders powder easier to ignite.
Oxidant salts or inert salts
Soluble salt is usually potassium nitrate, but some "inert" salts like potassium carbonate or Glauber-salt (sodium sulfate) were tried occasionally to use as a substituent salt. Saltpeter is, however, almost impossible to supersede in the powder like N 310. Nitro-cellulose is less easily soluble to Hoffmann's Drops, if nitrated into higher degree. Insoluble fibers of pyroxyline may lead the moisture into powder kernels. So it is more advisable to nitrify the cellulose to the lower degree, and add oxygen in the inorganic but oxidant salt.
Weight per unit of volume
Despite of rather high content of potassium nitrate, powder N 310 is among the least dense modern "smokeless" powders. One Cubic Centimeter (1.0 CC) of factory-fresh powder weighs just 0.50 grams or 7.7 grains; scooped with Lee Powder Measure Kit dipper along with directions and some years of experience.
Users of Powder Measure Kit may still find a column for ALCAN AL-120 powder from "slide rule" of that kit. Column is the last one at right on the side of quickly burning powders in a slide with a text "Copyright 1982". One Cubic Centimeter of AL-120 weighs the same 7.7 grains or ½ grams, just as N 310. According to hearsay it WAS Finnish N 310, but -- please -- NEVER trust on hearsay, gossips and other unconfirmed data, when developing handloads !!
Weigh before scooping !
Each and every user of Measure Kit have individual way to use the dipper. Therefore it is advisable to weigh several scooped charges of powder with a powder scale or other reliable scale. Average of ten scoopfuls of powder (1.0 CC each) can tell an exact specific weight of one cubic centimeter of powder. Variations more than 0.1 gr. tells about erratic use of the dipper. (Some peoples never learn the skill of scooping). Obtaining of powder measure device is advisable; especially buying one with a cubic centimeter main scale.
Continued to Part 2 >>
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