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GUNS Magazine October 2010 - Page 28
™ • HOLT BODINSON • Will the gas piston rifles replace the AR-15? o I hear a death rattle for Eugene Stoner’s direct-impingement, d gas operation system that’s been the cornerstone of the AR-15/M16/M4 platform? I think so, judging from the variety of 556 CLASSiC MAkER: SiG SAUER 18 inDUSTRiAL DR., ExETER, nH 03833 (603) 772-2302, www.SiGSAUER.CoM ACTion TYpE: Gas-piston rotary bolt semiauto CALiBER: 5.56 NATO, .223 BARREL LEnGTH: 16" oVERALL LEnGTH: 37.1" LEnGTH CoLLApSED: 34.3" LEnGTH FoLDED: 27.1" wEiGHT: 8 pounds, 6 ounces FiniSH: Black SiGHTS: 4-position rotary diopter; mini-red dot. Square front post. SToCk: Polymer pRiCE: $2,250 SiG’S SEnSATionAL MoDEL 556 re-engineered, gas-piston-driven uppers being offered to civilian and military markets today. More germane, the latest AR models have been designed from the ground up to maximize the use of the gas-piston engineering like FN’s Special Operations Forces Combat Assault Rifle (SCAR) and the SIG 556. Gas-piston technology is not unfamiliar in US weapon design. The M1 rifle, the M1 Carbine and the M14 rifle are excellent examples of long- and short-stroke, gas-piston designs. And let us not forget the king of the longstroke piston, Kalashnikov’s AK-47 and the widely distributed FN/FAL. Direct-impingement, gas operated systems are certainly not inherently deficient. The AR-15/M16 family of weapons has been continually refined and successfully engaged in some of the toughest armed conflicts for 48 years. In the civilian market, AR-15s have achieved an enviable reputation for competitive accuracy, and there is no finer treatise on wringing out the best in the design than the book written by our field editor, Glen Zediker, in his definitive The Competitive AR15. Yet, Eugene Stoner’s directimpingement gas operation system is inherently dirty when compared to similar systems. In milsurp circles, the finest direct-impingement gas system design I’ve seen is exhibited in the French MAS49 and MAS49/56 and secondarily in the Swedish Ljungman. The MAS features a directimpingement design in which a puff of gas is delivered from the gas tube into a small blind hole in the bolt carrier. The only significant fouling to contend with is the carbon deposited inside that short, blind hole, which can be readily wiped out with a Q-Tip. Compare that to having to tear down the M15/M16 bolt and bolt carrier for cleaning and having to worry about the arrangement of the gas rings on the bolt body itself. There’s no question the US military is definitely marching in the direction of the gas piston, and it’s time we took a look at recent gas-piston AR developments. This month we begin with the readily available SIG 556 semiauto civilian model. HandlingqualitiesoftheSIg556aresuperb.thehandguards(above)arewellventilatedand designedwithanergonomic“u”shape.thebarrelsportsaconventionalbird-cageflash suppressor.theSIg556(below)isblessedwithgreatergonomicdesignandlines. The Swiss are a shooting culture. The male population constitutes a well-trained, well-armed reserve force in which issued arms and a basic load of ammunition are maintained at home in their private residences. The advanced designs generated by Switzerland’s indigenous firearms industry, Schweizerische IndustrieGesellschaft (SIG) in Neuhausen am Rheinfall, have insured Switzerland’s long-standing reputation for finely crafted and exceedingly accurate arms. The new SIG 556 is no exception. In the 1950s, Switzerland fielded their radical looking Sturmgewehr 57 (StG 57), known also as the SIG 510 in commercial form, which replaced all of those lovely Schmidt-Rubins that have washed up on our milsurp shores. The StG 57 featured a delayed, rollerlock mechanism, based on an earlier Mauser design. A few years later, SIG introduced the Model 530 series chambered for 5.56 NATO. While the model still retained the roller-locking bolt, the stocking and outward profile of the SIG 530 family set the pattern carried on in the SIG 556 today. The next SIG generation to make its debut was the SIG 540 (5.56 NATO) and SIG 543 (7.62 NATO) in the early 1970s. The significance of this development with regard to the current 28 WWW.GUNSMAGAZINE.COM • OCTOBER 2010