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GUNS Magazine January 2010 - Page 20

UPONARS • GLEN ZEDIKER • FANTASTIC FORE-ENDS The big difference goes unseen. n virtually any venue where accuracy matters, a free-floating I barrel is an essential element. That means the barrel is attached to the receiver or action and touches nothing else, or nothing else nut on one end. The barrel nut secures the barrel into the upper in the same way as a standard configuration, and then the barrel just sticks out its other end. Now all the pressures put on the fore-end are directed to the upper receiver and not to the barrel. Float tubes come in a huge variety of configurations. That’s good news. The better news is nearly all are two-piece where the tube itself can come on and off while its attachment point remains on the rifle. Tubes designed for competitive shooting, such as NRA High Power Rifle, usually have vents and always a rail slot on their undersides to attach a handstop. The vents serve to both reduce tube weight and allow air circulation. They also catch wind. Some of us are going to smaller diameter float tubes to help improve “aerodynamics” for the standing position. touches it, either way. External pressures and contact points (which cause pressures) influence barrel vibrations and also where the barrel is “looking” shot to shot. I know it’s hard to believe something as stout as a heavy steel tube (a barrel) can be so easily persuaded to shift, but it can and will. It’s not so much the pressures and contacts themselves as it is their inconsistency. AR-15s with a standard-style handguard, whether carbine or rifle, have the front handguard cap, and also sling swivel, effectively attached to the barrel. Pressures against the handguard or sling swivel are transferred to the cap and, therefore, to the barrel. EasyFix This is too easy to fix on an AR-15. A “float tube” is essentially (if not actually) a piece of pipe with a barrel Cheesegraters Tactical-style float tubes are often covered over in Picatinny rails. 12, 3, 6, and 9 o’clock. Others allow customized attachment of rail mounting strips. Recommendations depend on what you’ll be mounting on the rails, but the customizable tubes usually feel better in the hand. I strongly suggest smoothing over any exposed and unused rails with specialty covers. Float tube diameters vary, and most of the NRA Match Rifle style are larger. They normally will fit right over the gas block or manifold. Some of the tacticalstyle float tubes don’t give much room to mix components. Generally, you’ll be fine if you get the fore-end and manifold from the same manufacturer. Specialized tubes exist for the NRA Service Rifle competitor to maintain the look of an A2 rifle, but still free-float the barrel and move the sling attachment point to the tube. It’s a very small diameter tube that allows the handguard pieces to snap in right over it. The front handguard cap and sling swivel mount are welded to one end of the tube and the Delta assembly is on the barrel nut as usual. There is no reason at all to choose Thisfore-endfromMedeshaFirearms(above)isonanacross-the-coursecompetitionrifle.Itis rotation-adjustableandhasarailslotforahandstopandaccessoryweight.Arail-to-railalignment fixture(bottom,leftfromBrownells)makesaligninga4-railfloattubewithaflattopupperasnooze. Thisisdanghandy,assomefloattubeshavealignmentmeansincorporatedbutmanyaretrialand error.OneofthebetterproductsoutthereistheDanielsDefensefloat-tube(bottom,right).Thisisa high-qualitypiece.Thisconfigurationisrifle-lengthoverall,butwithacutouttoaccommodatethe carbine-lengthgassystem.nice.TheBrownellsrailcoversmakeitevennicer. 20 WWW.GUNSMAGAZINE.COM • JANUARY 2010

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