Fore-End To The Forefront

The “Secret” To AR Accuracy

By Glen Zediker

The fore-end tube on an AR-platform firearm is essential to good on-target accuracy. Friend, gunsmith and AR-15 accuracy pioneer Derrick Martin (Accuracy Speaks) said it perfectly correctly a long time ago: “Float a good barrel.” That’s the “secret” to AR-15 accuracy.

Here’s why: The original ArmaLite/Stoner system has the two handguard pieces fitted into a receptacle attached to the barrel nut at the back and to the front sight housing at the front. Well, the front sight housing is likewise attached to the barrel and so too is the sling swivel. That creates a pressure point.

It may be hard to see how a sturdy metal tube (a barrel) can be “bent” by something as seemingly benign as a little pressure from a rifle sling looped around a shooter’s arm, or rested off the top of a fence post, but it dang sho is. The Bic Pen-contour barrel didn’t help any. Pressure points don’t really “bend” a barrel, but they suggest the direction the barrel will look during the pressure-induced vibrations and movement in firing. Steel becomes quite elastic under the pressures of firing (super-high-speed video shows downright frightening looking images when you can see the contortions going on way too quickly for the eye to detect).

In virtually every venue where accuracy matters, a free-floating barrel is an essential ingredient in the build. “Free-floating” means just as it says: the barrel doesn’t touch anything but its attachment point in the action or receiver. No pressure. The entire length of the barrel is suspended.

That’s what a tube-style fore-end does for an AR-15. Now the question is, what does the fore-end tube do for the shooter?

I think—but I’m not positive—the original “float-tube” debuted on the Rodman Labs experimental rifles in the 1960’s and do remember the first one I ever saw for sale was made of oil well recovery pipe. Now there is a vast array of fore-end tubes available. It’s gone wildly well-beyond specialized. It’s so specialized all I can really do is speak in generalities so, in general, here are a few ideas on how to choose and use a tube.

Most, by the way, are made of aluminum—a good metal for this job. Steel is too heavy. Carbon fiber tubes are available at a sometimes significantly higher cost. They are very light in weight and also are noticeably cooler to the touch during high-volume fire. There are various takes on heat shields as well and they’re welcome as the round count rises. Solid-style rail covers likewise help, since some AR’s can get exceedingly uncomfortable.

Glen strongly suggests the substitution of a carbine-length tube for a
rifle-length tube, if the configuration allows. It’s way better to shoot
with the longer tube. This one (right) is from Medesha Firearms and has
a cut-out to preserve the standard front sight housing mount.

Here’s a good tube from Daniel Defense. Not cheap to buy, not cheap in build
(they’re related). This is a rifle-length tube with carbine system cut-out areas.
This one has had the extra step taken of smoothing all the rail-cut edges, but
Glen still recommends the rail cover pieces. Brownells has ’em.

If you’re starting out with a conventional-style handguard system (2-piece plastic)
and you want to incorporate a tube, there are 2-piece float tubes split top and bottom.
Those allow installation without breaking down the barrel, and stripping all its parts.
Tubes need to install from the muzzle-end so front sight housing has got to go. They
work as well as a 1-piece, properly installed. This one is from Midwest Industries.

Yankee Hill tends to be one of Glen’s “go-to” tubes. They’re easy to install
on a straight index and accept rail pieces of varying lengths screwed down
where needed.

Competition Tubes

For across-the-course use, a float-tube will have a handstop attachment rail on its underside and usually a number of vents to relieve weight and provide cooling for the barrel. Make double-dang sure the topside is free of vents. It should be solid to reduce barrel-heat-induced mirage. If it’s not, get to a home store and buy a plastic Venetian blind replacement slat. Then attach it to the float tube with either two or three hook-and-loop double-sticky pads or zip ties. Works wonders! (I won’t show a photo of such in this nice magazine. It’s kind of like me showing you how to fix busted taillights with red tape.)

The better competition tubes are also longer than normal and my preference is a 15-inch (“standard” rifle-length is 12). Longer extends hand-positioning options for a long-armed shooter like me. I also suggest an extra-long tube for a varmint-style rifle since it also extends options for bipod positioning, and, I think, the geometry works better when the bipod is farther on out there. And same advice for a field gun: no vents on the top. Another competition-essential feature of a good tube is it can be rotated to suit the user’s preference in establishing rifle cant.

I have developed a preference for smaller-diameter tubes, and many of the competition tubes are a little big around for my tastes. Smaller circumference just fits my hand better and is also more “aerodynamic” so it doesn’t get caught and moved as much by wind.

Fore-end tubes for carbine-length barrels are better longer than shorter, in my belief. The “standard” 7-inch carbine tube length fits in behind a standard front sight housing (conventional carbine gas port location) but for me forces an uncomfortable, unsteady hold. A rifle-length tube is way on better. To get this to work, though, you’ll need to match up pieces to allow full coverage of the gas system within the tube. Plus, then you can mount the front sight on the tube at an extended distance. Win-win.

Speaking of mounting, most “tactical-style” fore-end tubes are covered with Picatinny rails at all four clock-face points. That’s fine, but for my own use I prefer a smooth tube with selectively attached mounting blocks. A smooth tube is simply more comfortable in my hand, and overall less obtrusive. Otherwise, I suggest considering rail covers for the unused exposed teeth. Those can snag.

If you have a fore-end tube on the gun, use it! It’s what should be the base for any attachments that won’t fit onto the upper receiver rail. Do not install anything onto the gas manifold. I know they are often provided with rail spots, but it’s still attached to the barrel and even consistent pressure is not as good as no pressure.

I have encountered clearance issues matching gas manifolds and float tubes. On a short gun I like the tube to cover the gas block and that means the manifold has to fit within the tube. Usually, choosing a gas block and float tube from the same manufacturer solves this quick like and in a hurry. Otherwise, choose a “low-profile” manifold.

The key to accuracy is “Float a good barrel.” Glen abides by the advice in
every build, including his colorful racing-inspired AR.

Shameless Self Promotion

The preceding was adapted from The Competitive AR-15: Builders Guide written by Glen and available at www.BuyZedikerBooks.com.

Accuracy Speaks
3960 N. Usery Pass Rd.
Mesa, AZ 85207
(480) 373-9499
www.accuracyspeaks.com

Brownells
200 South Front Street
Montezuma, IA 50171
(641) 623-4000
www.brownells.com

Daniel Defense
101 Warfighter Way
Black Creek, GA 31308
(866) 554-4867
www.DanielDefense.com

Medesha Firearms
10326 E. Adobe Rd.
Mesa, AZ 85207
(480) 986-5876
www.MedeshaFirearms.com

Midwest Industries
W292S4498 Hillside Rd.
Waukesha, WI 53189
(262) 896-6780
www.MidwestIndustriesInc.com

Yankee Hill Machine
20 Ladd Avenue, Suite 1
Florence, MA 01062
(413) 584-1400
www.yhm.net

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