• h O L t B O d I N S O N • Arthur Langsford at his gun shop in Broken hill, Australia. bore, anti-tank cannons like the 42mm PAK 41 that fired a 42mm Gerlichtype projectile that left the muzzle as a 30mm shell after having been squeezed down in a smaller diameter, smoothbore portion of the barrel. In the US, there was also some early work in 1942-43 at the Frankfort Arsenal Laboratory, which focused on the .50 BMG cartridge loaded with sub-caliber 30- and 35-caliber bullets encased in either ventilated, collapsing jackets or disintegrating sabots. While the experiments were terminated in 1943 for more pressing war time priorities, the sabot design did reemerge later as the current .50 BMG Saboted Light Armor Penetrator “SLAP” round. LANGSfORd’S SqUEEZE-BORE RIMfIRES Is this near-forgotten idea too good to die? aper-bores are the stuff dreams are made of. Imagine T firing a bullet that begins life as one caliber down a bore that progressively gets smaller and smaller in diameter. What emerges is a bullet of smaller caliber with an improved ballistic coefficient at a relatively high velocity. The late Australian gunsmith and cartridge designer, Arthur Langsford, had a better idea. Why not just dispense with the taper-bore design and simply fire a conventional .22 Long Rifle cartridge down a 17- or 20-caliber barrel and see what you get? What he got is one of the most intriguing stories in rimfire history. Langsford’s earliest rimfire experiments centered around the development of sub-caliber wildcats using unloaded ICI .22 LR shot cases, no less, necking them down to .17 as his “Minor-Mite” and “Vixen” cartridges as well as his “Tini-Mite” series in .08, .11, .14 and .17 calibers. The .17 TiniMite was actually produced and sold in some quantity through his Myra’s Sports Store in Broken Hill, Australia. None was quite the commercial success he had hoped for, but Langsford was 20 years or so ahead of the commercial appearance of the 5mm Remington Rimfire Magnum, .17 HMR and .17 Mach 2. Arthur Langsford just went 18 Extruders But back to Mr. Langsford and his “Extruders.” That’s what he called his new cartridge series—the Extruders— actually the “Myra Extruders”— Myra being his wife. Langsford’s solution to the squeeze-bore challenge called for the use of a standard diameter 17- caliber or 20-caliber barrel with 1:6.5" to 1:8" twist. While the barrel was chambered for the conventional .22 Long Rifle cartridge, the secret lay in the form of the throat or lead. Langsford designed a forcing cone in the throat that eased the bullet into the smaller bore without damaging it. The picture (sorry, but these were Langsford’s original photographs) illustrating the gradual transformation of a .22 bullet into .17 projectile clearly shows the angle and structure of the forcing cone. He called his squeeze-bore design the “Myra on to pursue a better idea. He reckoned if using a soft lead bullet he might be able to squeeze it down in caliber and still achieve reasonable accuracy as well as higher velocity and an improved bullet form. Jacketed bullets had always proved a problem in taper-bore guns. Some of the better known experiments included the German Gerlich gun using a flanged bullet that gradually collapsed as it progressed down a tapered-bore barrel. While taper-bore barrels proved expensive and a pain to make and were subsequently abandoned, during WWII, Germany did field squeeze- Did Langsford ever build and use his pressure gun? We’ll never know. WWW.GUNSMAGAZINE.COM • JANUARY 2011
Share
Print
Archive
.
